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Investigation of pressure drop in horizontal pipes with different diameters
Abstract
The pressure drop has a significant importance in multiphase flow systems. In this paper, the effect of the volumetric quality and mixture velocity on pressure drop of gas-liquid flow in horizontal pipes of different diameters are investigated experimentally and numerically. The experimental facility was designed and built to measure the pressure drop in three pipes of 12.70, 19.05 and 25.40 mm. The water and air flow rates can be adjusted to control the mixture velocity and void fraction. The measurements are performed under constant water flow rate (CWF) by adding air to the water and constant total flow rate (CTF) in which the flow rates for both phases are changed to give same CTF. The drift-flux model is also used to predict the pressure drop for same cases. The present data is also compared with a number of empirical models from the literature. The results show that: i) the pressure drop increases with higher volumetric qualities for the cases of constant water flow rate but decreases for higher volumetric qualities of constant total flow rate due to the change in flow pattern. ii) The drift-flux model and homogenous model are the most suitable models for pressure drop prediction.
... All existing models [12][13][14] cited in this study generally consider that the contribution of the acceleration pressure drop is less than 5%, and therefore, it is often chosen to be neglected. 15 This approach may be appropriate in classical gas-liquid two-phase flow. However, in ALPs, when the void fraction exceeds a certain value, the contribution of the acceleration pressure drop can reach 6%-11%. ...
... The experimental results for the pressure drop are shown in Fig. 8. Combining Figs. 4 and 8, it can be observed that when the void fraction is less than 60%, the proportion of the acceleration pressure drop is less than 5%. This result validates the view of Hamad et al. 15 that the acceleration pressure drop can be neglected. However, when the gasliquid void fraction exceeds 60%, the proportion of the acceleration pressure drop reaches 6%-11%. ...
... Chisholm 14 provided a relationship to calculate the two-phase friction multiplier based on the pressure drop in the liquid phase, as shown in Eq. (15). Chisholm 14 used C/X to quantify the effect of the pressure drop between the gas and liquid phases, where C/X is given by ...
Airlift pumps (ALPs) are promising in the oil and chemical industry, owing to their advantages such as a simple structure, convenient operation, wide applicability, high cost-effectiveness, environmental friendliness, safety, and reliability. However, there are few studies on the frictional pressure drop of vertically upward gas–liquid two-phase flow in ALPs. Therefore, this study presents an experimental investigation of the frictional pressure drop in the vertically upward gas–liquid two-phase flow in ALPs. Experiments were conducted in a vertical pipe with a total length of 3.245 m and a two-phase section of 2.8 m; the working pressure of the air compressor was 0.4 MPa, pipe diameter was 0.05 m, submergence ratio ranged from 0.6 to 0.85, and gas superficial velocity ranged from 0 to 4 m/s. A total of 74 sets of experimental data were obtained, and the frictional pressure drop models of 36 classical gas–liquid two-phase flows were evaluated. The results indicated that classical gas–liquid two-phase flow models significantly underestimated the experimental results. By analyzing the experimental data, visualizing the internal flow field, and performing theoretical derivations, a new frictional pressure drop correlation was established for the vertically upward gas–liquid two-phase flow in ALPs. The results demonstrated that the new model could accurately predict the frictional pressure drop of ALPs with mean percentage error, mean absolute percentage error, and root mean square percentage error values of 7.8%, 12.18%, and 25.86%, respectively.
... Flowing oil, gas, and water in subsea pipelines is a typical example of multiphase flow. Accurate determination of design parameters such as pressure drop, liquid hold up, friction factor, bubble size, void fraction, heat and mass transfer coefficient is required for optimum design of specific application equipment (Hamad et al., 2017). Among the parameters above, accurate estimation of pressure drop is paramount for characterization of flow patterns, estimation of pipe's wall shear stress and interaction of flow structure. ...
... However, the leading methods in the field often return the experimental multiphase flow pressure drop with more than 50% error (Moreno Quibén and Thome, 2007a;Ould Didi et al., 2002;Revellin and Thome, 2007). Interaction between the phases, motion and deformation of the interface, and non-equilibrium effect are the main characteristics of multiphase flow, making it complex for modelling (Angeli and Hewitt, 1998;Hamad et al., 2017;Xu et al., 2012). ...
... Despite the limitation that this method might exhibit, it is still very prevalent for the perdition of frictional pressure drop in the industry for practical applications such as nuclear power plants and heat pump systems and evaporators in refrigeration (Awad, 2012). Friedel (1979) Friedel, (1979 (Friedel, 1979) used an extensive data bank in different conditions to develop his model for estimating frictional pressure drop (Friedel, 1979;Hamad et al., 2017;Moreno Quiben, 2005). The author obtained the model by taking into account the effect of gravity (g) through the Froude number (Fr) and including the surface tension (σ) and total mass flux by using the Weber number (We); then, he optimized the two-phase frictional multiplier (Φ f 2 ) introduced earlier by (Lockhart and Martinelli, 1949) Lockhart and Martinelli, (1949). ...
The two-phase frictional pressure drop has a dominant effect in many industrial applications associated with the multiphase flow. This study investigated the accuracy of several available methods for predicting two-phase frictional pressure drop of different pipe diameters using 4124 experimental data points. It is observed that the performance of the existing methods is poor in a wide range of operating conditions. Then, several Artificial Neural Network models were proposed, including six multilayer perceptron (MLP) and one Radial Basis Function (RBF) using the same data sets. The weights and biases of the ANNs were optimized using Levenberg-Marquardt (LM), Bayesian Regularization (BR), Scaled Conjugate Gradient (SCG), Resilient Backpropagation (RB), Particle Swarm Optimization (PSO) and Genetic Algorithm (GA). Statistical error analysis indicates that neural network incorporated with the Genetic Algorithm (MLP-GA) predicts the entire data set with a Root Mean Square Error of 0.525 and an Average Absolute Relative Error percentage of 6.722. Finally, the sensitivity analysis was carried out, indicating that the mass flux (G) has the highest direct impact on the two-phase frictional pressure drop.
... Flowing oil, gas, and water in subsea pipelines is a typical example of multiphase flow. Accurate determination of design parameters such as pressure drop, liquid hold up, friction factor, bubble size, void fraction, heat and mass transfer coefficient is required for optimum design of specific application equipment (Hamad et al., 2017). Among the parameters above, accurate estimation of pressure drop is paramount for characterization of flow patterns, estimation of pipe's wall shear stress and interaction of flow structure. ...
... However, the leading methods in the field often return the experimental multiphase flow pressure drop with more than 50% error (Moreno Quibén and Thome, 2007a;Ould Didi et al., 2002;Revellin and Thome, 2007). Interaction between the phases, motion and deformation of the interface, and non-equilibrium effect are the main characteristics of multiphase flow, making it complex for modelling (Angeli and Hewitt, 1998;Hamad et al., 2017;Xu et al., 2012). ...
... Despite the limitation that this method might exhibit, it is still very prevalent for the perdition of frictional pressure drop in the industry for practical applications such as nuclear power plants and heat pump systems and evaporators in refrigeration (Awad, 2012). Friedel (1979) Friedel, (1979 (Friedel, 1979) used an extensive data bank in different conditions to develop his model for estimating frictional pressure drop (Friedel, 1979;Hamad et al., 2017;Moreno Quiben, 2005). The author obtained the model by taking into account the effect of gravity (g) through the Froude number (Fr) and including the surface tension (σ) and total mass flux by using the Weber number (We); then, he optimized the two-phase frictional multiplier (Φ f 2 ) introduced earlier by (Lockhart and Martinelli, 1949) Lockhart and Martinelli, (1949). ...
... The system of equations for the 1D conservation laws in an isotropic isothermal medium, assuming the drift-flux model with no mass transfer between the gas and liquid phases and using a superficial velocity in porous medium (u sk = εu k , where ε is the porosity and the subscript k refers to liquid or gas phase whereas s denotes superficial) can be given by Eqs. (13)- (15). The first two equations consist of mass formulations for each phase (liquid and gas) with the last equation representing the momentum of mixture. ...
... The comparison between experimental and predicted values reported by Hamad et al. [15] is shown again in Fig. 3. ...
... Earlier in Hamad et al. [15], the solver proposed in Santim and Rosa [36] which uses the Drift-Flux model showed to be a great choice on the prediction of the pressure drop in horizontal pipes with different ID and non-porous media. Now, assuming two different porous media and two pipes of 0.0254 m and 0.01905 m ID, the solver is compared together with the empirical models proposed by Jamialahmadi et al. [17] and Nemec and Levec [28] against the experimental two-phase flow data in Figs. 8 and 9. ...
This study investigates the pressure drop in horizontal pipes packed with large particles that result in small pipe-to-particle diameter ratio both experimentally and numerically. Two horizontal pipes of 0.1905 and 0.0254 m ID filled with cylindrical or spherical particles are used to collect the experimental data for single and two-phase flows. The porosity has same value for both pipes when they packed with cylindrical particles which is 0.75, however has different values when packed with spherical particles, 0.7 for the large pipe and 0.57 for the small pipe. The Roe-type Riemann solver proposed by Santim and Rosa Int J Numer Methods Fluids 80 (9), 536–568, [36] which uses the Drift-Flux model is modified aiming to predict the pressure drop in porous media through the implementation of a new source term in the system of equations. Empirical models available in the literature are used to calculate the single and two-phase flows pressure drop. The motivation is to verify the solver capability to reproduce the two-phase flow pressure drop in porous media and to compare some empirical models existing in the literature against the experimental data provided modifying some empirical coefficients when necessary.
... Meanwhile, the pressure gradient decreases significantly as pipe size increases. A similar trend was observed by Hamad et al. (2017). Once the pressure gradient is obtained, in the process of calculating the two-phase multiplier in Equation (4-1), the predictions of frictional pressure gradient in single-phase flows are obtained by the Blasius formulation, since this equation has been validated by many previous studies (Hamad et al., 2017;Bowden and Yang, 2016). ...
... A similar trend was observed by Hamad et al. (2017). Once the pressure gradient is obtained, in the process of calculating the two-phase multiplier in Equation (4-1), the predictions of frictional pressure gradient in single-phase flows are obtained by the Blasius formulation, since this equation has been validated by many previous studies (Hamad et al., 2017;Bowden and Yang, 2016). In Figure 4-4 (a), the ϕf calculated based on the experimental data and Blasius equation are plotted against X in the horizontal flows. ...
... It is surprising to note that very limited studies have been performed in moderate (10 mm < ID < large diameter pipes, it is found that the average disagreement between measured and predicted pressure drop using previous models can easily exceed ±20% (Ferguson and Spedding, 1995;Hamad et al., 2017). While the analysis on frictional pressure drop requires reliable experimental databases established based on strict experimental controls (e.g. ...
The highly asymmetric void distribution in horizontal two-phase flow due to buoyancy adds further complications to the study of horizontal flow, both experimentally and analytically. As such, there has been limited research on horizontal two-phase flow, comparing with the extensively studied vertical two-phase flow. However, understanding of horizontal two-phase flow is essential to the correct simulation of two-phase flow in engineering systems such as nuclear power plant. With this in mind, the current work characterizes the horizontal air-water two-phase flow in straight pipes of different pipe sizes. An extensive experimental database is established for both global and local two-phase flow parameters in 38.1 mm and 101.6 mm ID pipes, using high-speed video camera, pressure transducer and local four-sensor conductivity probe. A specially designed instrumentation port is employed for local probe measurements by considering the asymmetric gas distribution. A wide range of flow regimes is investigated including horizontal bubbly, plug and slug flows. Some of the major characteristic two-phase flow phenomena of interest include flow regime transitions, two-phase frictional pressure drop, local interfacial structures, and one-dimensional drift-flux analysis. Considering that the bubble size to pipe diameter ratio may govern the asymmetry of the gas distribution, the effects of pipe size on flow regime transitions are investigated. The flow regime maps for horizontal two-phase flow in reactor system analysis codes TRACE and RELAP are evaluated and improvements are suggested. Effects of pipe size on local two-phase flow parameters and further on the flow regime transition are observed. Due to the importance of pressure drop in the engineering system design, a systematic study is performed to investigate the effects of pipe size, flow regime, and flow orientation on two-phase frictional pressure drop analysis in straight pipes. Various modeling approaches are evaluated and methods with the best performance are recommended. Finally, the one-dimensional one-group IATE for horizontal air-water bubbly flow applicable to different pipe sizes is developed. The closure relations are developed based on the more comprehensive experimental database. As a result, the IATE for horizontal bubbly flow can predict measured with an averaged percent difference of ±5.2%, except for the conditions near the transition boundary where large bubbles are generated as flow develops.
... Systematic studies on the effects of flow orientation, flow regime and pipe size on frictional pressure drop analysis are not available in previous research. In addition, among the existing studies in moderate and large diameter pipes, it is found that the average disagreement between measured and predicted pressure drop using previous models can easily exceed ± 20% (Ferguson and Spedding, 1995;Hamad et al., 2017). While the analysis on frictional pressure drop requires reliable experimental databases established based on strict experimental controls (e.g. ...
... Fig. 4(a) and (b) show the pressure gradient due to friction only in horizontal bubbly flow and plug/slug flows, respectively. The results show that the pressure gradient increases with increasing j g , which was also observed by previous work (Müller-Steinhagen and Heck, 1986;Shannak, 2008;Hamad et al., 2017). Meanwhile, the pressure gradient decreases significantly as pipe size increases. ...
... Meanwhile, the pressure gradient decreases significantly as pipe size increases. A similar trend was observed by Hamad et al. (2017). ...
... [9][10][11][12][13][14] The gas-liquid pressure drop not only inherits the complex phenomena of single phase, such as nonlinearity, transition to turbulence and instability, but also contains additional characteristics like gas-liquid slip, two-phase interfacial movement and distortion, interphase mass and energy transfer, which leads to a more complex prediction of gas-liquid pressure drop. 4,15,16 Analyzing and predicting two-phase pressure drop becomes especially difficult when additional factors such as liquid properties, flow rates, and pipe structure are further considered. 10,15,[17][18][19][20] In the horizontal two-phase flow, under the action of interphase density difference and gravitational acceleration, different superficial gas-liquid velocities show different phase interface structures in the pipe, such as annular flow, slug flow, bubble flow, and stratified flow. ...
... 4,15,16 Analyzing and predicting two-phase pressure drop becomes especially difficult when additional factors such as liquid properties, flow rates, and pipe structure are further considered. 10,15,[17][18][19][20] In the horizontal two-phase flow, under the action of interphase density difference and gravitational acceleration, different superficial gas-liquid velocities show different phase interface structures in the pipe, such as annular flow, slug flow, bubble flow, and stratified flow. Horizontal slug flow, due to its higher pressure loss and periodic characteristics, is a significant concern in the assessment of transport capacity, pressure loss calculation and corrosion protection design for multiphase pipelines. ...
Accurate prediction of the horizontal slug pressure drop is valuable for optimizing the multiphase pipeline transport process and ensuring the stable operation of the pipeline systems and treatment facilities. Experimental slug pressure drop research is conducted based on differential pressure signals in the short (0.065 m ID, 215D) and long (0.046 m ID, 35 957D) horizontal pipes. A slug pressure drop database in horizontal pipes is constructed over a wider range of pipe diameters (0.030–0.3 m), liquid viscosities (0.0101–6.25 Pa⋅s), and pipe lengths (6–1657 m). The slug pressure drop increases with decreasing pipe diameter, while the distribution range of slug pressure drop vs the superficial gas velocity rises with increasing liquid viscosity. The 26 pressure drop prediction models are evaluated for their ability in the horizontal slug pressure drop database with different pipe structures and fluid properties, and the best pressure drop correlations are selected for the low, medium, and high liquid viscosity ranges. Accordingly, a combined pressure drop prediction approach of horizontal slug flow based on liquid viscosity classification is proposed with a Pearson's correlation coefficient of 0.987, and the average absolute percentage error is reduced from 44.98% to 30.14%. Based on the Lockhart–Martinelli method, a prediction correlation for horizontal slug pressure drop is developed over a wider range of pipe diameters and liquid viscosities, and industrial near-horizontal pressure drop data are successfully predicted with 89.6% of the data in the error interval of ±20%.
... For instance, pressure drop experimental data in horizontal air-water flow were reported by Hernández-Pérez [21]. In a more recent work, Hamad et al. [22] reported data for three different pipe diameters using air-water mixtures. Due to the short length of their pipes (1 m), the flow pattern was created in such a way that it was always homogeneous. ...
... Ortiz-Vidal et al. [34] reported pressure drop data with uncertainty within ±8.5% depending on the flow conditions. Hamad et al. [22] compared single-phase pressure drop data with the Blasius equation and determined that the error associated with the pressure drop measurements is within the range (±10%). This shows the importance of reliable experimental data in improving the performance of prediction methods. ...
Experimental data for frictional pressure drop using both air–water and air–oil mixtures are reported, compared and used to evaluate predictive methods. The data were gathered using the 2-inch (54.8 mm) flow loop of the multiphase flow facility at the National University of Singapore. Experiments were carried out over a wide range of flow conditions of superficial liquid and gas velocities that were varied from 0.05 to 1.5 m/s and 2 to 23 m/s, respectively. Pressure drops were measured using pressure transducers and a differential pressure (DP) cell. A hitherto unreported finding was achieved, as the pressure drop in air–oil flow can be lower than that in air–water flow for the higher range of flow conditions. Using flow visualization to explain this phenomenon, it was found that it is related to the higher liquid holdup that occurs in the case of air–oil around the annular flow transition and the resulting interfacial friction. This additional key finding can have applications in flow assurance to improve the efficiency of oil and gas transportation in pipelines. Models and correlations from the open literature were tested against the present data.
... At the bottom of pipe, the heavier fluid tends to settle and at the top of the pipe, the lighter fluid tends to concentrate. During the flow different flow patterns appear when the flow rates of both the phases are varied [14]. The flow patterns have more complex nature due to the gravitational force which acts perpendicular to the axis of pipe and flow direction. ...
... The pressure drop in a pipe or channel occurs due to the variation of potential and kinetic energies of flowing fluid through it. This type of variation in the energies arises due to friction on the walls of pipe or channel [14]. For single-phase flows and multiphase flows, the % DR is given as follows [19]. ...
This paper suggests and discusses different drag reduction methods for two-phase horizontal flows through pipes. Two-phase flows are the simplest and most common among the multiphase flows, and have a great importance in real life. Drag reduction can be achieved through the addition of drag reducing additives or agents in the flow system and such method is known as additive method. Drag reducing agents include solid suspensions, polymers and surfactants. Two types of additives exist, soluble and insoluble additives. Insoluble additives include solid suspensions and soluble additives include polymers and surfactants. Nanofluids are also used as drag reducing agents. Combined methods of drag reduction also exist where two different drag reduction methods are used together to achieve drag reduction. The drag reduction is well achieved through solid suspensions, polymers, surfactants and nanofluids. It was also found that combined methods of drag reduction showed more drag reducing ability than methods used separately. From an environmental perspective, the biopolymers are more effective than synthetic ones due to some desirable properties of biopolymers such as cheap, non-toxicity, renewability, bio-degradability, stability, biocompatibility and easy availability.
... Two phase flow phenomena are often encountered in various industrial applications such as petroleum, power plant, nuclear reactor technology, food production, chemical process, aerospace and automotive industries [39,40], and sewage pipelines [41]. Twophase flow can be solid-liquid flow, liquid-liquid flow, gas-solid flow, and gas-liquid flow. ...
... These mixtures may produce different geometric configurations, which are usually referred to as regimes or flow patterns. The flow regimes occur due to instability of flow and are influenced by physical properties of the fluid such as gravity and density viscosity, surface tension, and the flow system geometry [40]. One of the key issues in the design of urban drainage systems is the integrity of the system structure under hydraulic overloading. ...
The design of above ground building drainage systems follows codes and standards that only give cursory recognition to the fact that this system connects, in the majority of cases, directly to a vast network of sewer pipes leading to a wastewater treatment plant. At the same time, for underground systems, airflow within as well as in and out of sewers is often neglected during the design of sewers, which depend on these building installed systems for pressure relief and venting. There is clearly an interaction between the two systems, yet this is not reflected in the design guidance, particularly inside buildings where air pressure fluctuations can lead to the destruction of water trap seals and the ingress of foul air containing sewer gases and potentially harmful pathogens. In this systematic review of historical research and design practice for both above and belowground drainage systems, we present the current state of the art and make recommendations for advancements that recognise the interaction between systems and present a view on how design could be advanced in a more holistic way.
... Using this approach, the frictional pressure drop analysis was performed by Kong and Kim [8] in a 38.1 mm ID horizontal pipe. Hamad et al. [9] investigated the pressure drop in horizontal pipes with three different inner diameters (13 mm, 19 mm, and 25 mm). The authors suggested homogeneous flow model and drift-flux model for frictional pressure drop prediction in two-phase flow. ...
... Therefore, the value of C is only a function of G for given fluids according to Eqs. (6)- (9). ...
In literature, there exists very limited work to systematically investigate the effects of pipe size on horizontal two-phase flow. The ratio between the characteristic bubble length scale and the pipe diameter may govern the severity of the asymmetry, which leads to
fundamental differences in the relative motion between the two phases. Meanwhile, additional work needs to be performed to evaluate the closure models for horizontal
flow in conventional nuclear reactor analysis codes.
... The pressure drop has a significant importance in multiphase flow systems. [20][21][22][23][24] In this regard, various researchers have hereunto tried to correlate the pressure drop in the extraction columns. A number of proposed correlations in this field are listed in Table 1. ...
... In addition, an easy access to E m at different stage configurations is possible through Eq. (22) for determination of C p or by an expression for C E p derived by combining Eqs. (22) and (20), as follows: ...
This article deals with the evaluation of pressure drop and consumption of energy for a steady-state solvent extraction in a horizontal pulsed sieve-plate column, which are important for the design and optimization of the periodic-flow processes for industrial applications. In this study, the pressure drop and the position of loading points are investigated. Moreover, a mathematical evaluation on the energy consumption in the case of a pulsed flow is conducted, and besides the influence of pulsation intensity, the effect of geometrical parameters including the plate spacing and plate-free area is investigated as well. The results of this study are helpful for optimization of column geometry targeted to higher performance and lower energy consumption.
... Using this approach, the frictional pressure drop analysis was performed by Kong and Kim [8] in a 38.1 mm ID horizontal pipe. Hamad et al. [9] investigated the pressure drop in horizontal pipes with three different inner diameters (13 mm, 19 mm, and 25 mm). The authors suggested homogeneous flow model and drift-flux model for frictional pressure drop prediction in two-phase flow. ...
... Therefore, the value of C is only a function of G for given fluids according to Eqs. (6)- (9). ...
... The experimental uncertainty is the combined effect of utilised materials (e.g. bentonite, deionised water and CSPs) and the accuracy of the experimental apparatus (viscometer, filter press, spectrometer and microscope) and the operating conditions (temperature, pressure and recorded time) (Hamad et al. 2017). The effect of these variables leads to some errors in the rheological properties of the formulated mud that need to be recognised. ...
Meeting the global energy demand and sustainable development of conventional petroleum reserves necessitates the development of high-performance and environmentally friendly water-based drilling fluids (WBDF). Nevertheless, one of the major concerns of using WBDF is the fluid loss due to its penetration into the formation during the drilling operation. Various additives (fluid-loss agents) in the industry have been introduced to tackle the issue but at the cost of non-biodegradable hazardous chemicals. Due to the recent interest in environmentally friendly WBDF additives, this study looked at the suit-ability of the composite part of peanut shell powder (CSP). The CSP was selected because of affordability, accessibility and fibrous content. Following the American Petroleum Institute (API) guidelines for preparing the drilling mud additives, six different laboratory experiments were carried out for biodegradable drilling fluids prepared from CSP at different concentrations of 1, 2 and 3 wt% and particle sizes (fine, 224 μm and medium, 1.12 mm). Major elemental and temperature analyses of the samples were conducted using Energy-dispersive X-ray Spectroscopy (EDX), Fourier Transform Infrared spectroscopy (FTIR) and a Thermogravimetric Analyser (TGA). Comparing the results with the referenced WBDF indicates that adding 1, 2 and 3 wt % fine CSP decreases the fluid loss by 37%, 50% and 65%, respectively. In addition, using medium-size CSP in the same concentration of 1, 2 and 3 wt % reduced the fluid loss by 30%, 39% and 53%, respectively. Based on the results, the use of fine particle size CSP with a 3 wt % weight concentration is recommended, as it creates a thin mud cake with lower permeability, allowing for better control of fluid loss.
... When variables such as fluid properties, flow rate, and pipe diameter are added to the equation, the problem becomes more difficult. 79,[86][87][88][89][90] Many researchers have obtained a large number of two-phase pressure drop data in simple pipelines (horizontal pipe, vertical upward pipe, downwardinclined pipe, and upward-inclined pipe) and proposed various prediction models accordingly. Based on the classification methods proposed by Xu et al., 80 Mekisso, 91 Ghajar and Bhagwat, 87 and Arabi et al., 83 the existing prediction models can be divided into the separated flow model, homogeneous flow model, empirical model, and phenomenological model. ...
To ensure the flow safety of the offshore gathering pipeline system, it is critical to study the large-scale pressure wave propagation behavior and predict the two-phase pressure drop in the subsea pipeline. In this paper, the local flow structure, pressure wave propagation characteristics, and two-phase pressure drop of the horizontal pipeline are obtained in a long-distance pipeline S-shaped riser system with a diameter of 46 mm and a total length of 1722 m. The overall-local correlation flow pattern map in the pipeline–riser system is proposed. The propagation modes of the pressure wave induced by the riser's pressure fluctuation in the horizontal pipeline under different overall flow patterns are clarified, and the correlations for predicting the propagation velocity and the attenuation coefficient of the pressure wave are proposed. The correlation for predicting the two-phase pressure drop of long-distance horizontal pipeline in the pipeline–riser system is established, and 88.23% of the data are within the error interval of ± 10%.
... Peneliti lainnya dengan kajian serupa seperti Sugiyanto & Anmar (2018) [7] , yang melakukan penganalisaan pada sistem perpipaan pompa sentrifugal untuk keperluan pemadam kebakaran. Mahardhika dkk.(2022) [8] melakukan evaluasi tegangan sistem perpipaan pada air gan compressor, dan Hamad dkk (2017) [9] melakukan kajian penurunan pada sistem perpipaan dengan pendekatan 2 fase. Sementara itu pada penelitian Sulu, & Temiz (2023) [10] Melakukan kajian terhadap karakterisasi mekanis dari sistem perpipaan komposit yang dilakukan penyambungan dengan pipa dengan jari-jari yang berbeda dengan tekanan internal tertentu, dan Qu dkk. ...
The piping system is a fundamental process equipment in the industry. The phenomena that occur in piping systems vary depending on the conditions of the pipes and the fluids flowing through them. Therefore, research related to piping systems requires attention to minimize and understand the occurring phenomena. There have been many studies related to piping analysis, but what sets this research apart from previous studies is that it focuses on examining the contribution of each component of the piping system to friction loss-pressure drop. Furthermore, the data obtained is used to determine the deviation or difference between experimental data and theoretical calculations. This research aims to study the correlation between friction loss and pressure drop in piping systems (including pipes, elbows, and tees) and to determine the extent of deviation between theoretical calculations and actual conditions, as well as to understand the trend of such deviations. Results show that as the length of the pipe increases, there is an increase in pressure drop, especially for pipe lengths of 0.6, 0.8, and 1.4 meters, the values are 275.26, 367.0, and 642.27 Pa over density, respectively. Conversely, as the pipe diameter increases, the resulting pressure drop becomes smaller, namely for pipe diameters of 0.5, 0.75, and 1.25 inches, the values are 266.64, 93.33, and 13.33 Pa over density, respectively. In the observation of the influence of fittings, it is shown that the pressure drop generated by elbows is greater than that of tees, with values of 26.66 and 13.33 Pa over density, respectively. When calculating the percentage deviation, there is a tendency for longer pipes and larger diameters will increase the percentage of deviation. For pipe lengths of 0.4, 0.6, and 1.4 meters, the percentage deviations are 3.23, 10.11, and 17.50%, respectively. For variations in pipe diameter, the percentage deviations are 3.23, 41.74, and 47.15% for diameters of 0.5, 0.75, and 1.25 inches, respectively. Meanwhile, the percentage deviation for tees is greater than that of elbows, with values of 84.78% (for elbows) and 185.02% (for tees).
... [20], found that pressure drop was higher in perforated horizontal wellbores with a 90º angle phase compared to those with 0º and 180º angle phases due to the increased influence of mixing pressure drop on increasing swirling. [21], observed that liquid holdup increased when the liquid flow rate increased, and they also noticed that the max flux and pressure drop increased at an increased liquid holdup fraction. [22], investigated flow patterns and pressure drop in the horizontal pipe and observed that the stratified flow pattern was obtained through the horizontal pipe only when the liquid flow was located at the bottom wall, while gas flowed at the upper wall of the horizontal pipe. ...
This study examined the intricate interaction between flow patterns and production within a perforated horizontal wellbore. The study precisely assessed the behavior of static pressure drop by utilizing an array of flow regimes encompassing bubble, dispersed bubble, transitional bubble/slug, slug, stratified, transitional slug/stratified wave, and stratified wave. Remarkably, an upward trend in static pressure drop was observed with increasing water phase presence, while the converse was true for the air phase. Besides, the air phase superficial velocity exhibited a direct correlation with the magnitude of pressure drop fluctuations. The liquid production demonstrated a peak during bubble and slug flow regimes, followed by a descent during the transition to stratified and stratified wave flow. This decline can be attributed to mixing pressure drops localized during the perforations. Furthermore, an upward trend in average liquid production was observed with increasing mixture superficial velocity, primarily due to the dominant presence of the water phase. Additionally, the percentage of liquid production was positively associated with the water's superficial velocity when the air's superficial velocity was held constant. While the experimental and numerical results were in agreement for slugs and structured flows, there were discrepancies in the behavior of static pressure for bubbles, small bubbles, and structured waves.
... During multiphase flow, different flow patterns can be seen even if the rates of air and water flow fluctuate. Liquids' physical characteristics, such as viscosity, surface tension, density, and the flow system's shape, all have an impact on these flow patterns (Hamad et al., 2017). The pressure drop, liquid and gas holdup, and flow pattern were identified as the crucial elements of multiphase flow by Almutairi et al. (2020). ...
... The optimizing pipe string process is suitable for little water production gas wells with certain self flowing capacity, which are generally characterized by large tubing-casing pressure difference and rapid decline of production. Conventional foam drainage and gas lift are effective, but the gas lift is short in validity or can not meet the requirements for water drainage (Waltrich et al., 2015;Hamad et al., 2017). ...
With the scale development of shale gas, the importance of selecting appropriate deliquification process has become increasingly evident in maintaining well productivity and improving shale gas recovery rate. At present, the preferred deliquification process are macro-control plate method and field experience method. The existing methods can only qualitatively select the deliquification process by considering limited influencing factors, resulting in poor process implementation. Based on the results of error analysis, the Gray model was optimized to calculate the pressure distribution in the shale gas wellbore and determine the applicable pressure limit. The W.Z.B. empirical model, which fully considers the influence of wellbore inclination, is used to calculate the gas-liquid carrying situation and determine the applicable liquid carrying limit. By analyzing the technical limits of five commonly used deliquification processes in the Changning shale gas field, namely, plunger lift, optimizing pipe string, gas lift, foam drainage, and intermittent production, a quantitative optimization method for deliquification processes was established. This method was then used to obtain the optimization chart for deliquification processes in shale gas wells. This method was applied in Well Ning 209-X, where the corresponding optimization chart for deliquification processes was drawn based on the production characteristics of the gas well. By quantitatively optimizing the deliquification processes and adjusting to suitable techniques, it effectively guided the production of the gas well and improved the gas field recovery rate.
... Similarly, Fig. 4(b) shows that as the operating temperature rises, resulting in decreased oil viscosity, the frictional pressure gradient also decreases. The influences of pipe diameter and liquid viscosity on the frictional pressure gradient are consistent with previous studies [68,[105][106][107][108]. ...
This study focuses on the frictional pressure drop in gas-liquid two-phase flow, characterized by nonlinear behavior under various flow conditions due to complex two-phase phenomena. The experimental investigation involves an air-oil mixture flowing through horizontal pipes with diameters of 20 mm and 40 mm, aiming to observe the flow patterns and quantify the pressure drop. Two oils with different thermophysical properties are used as the liquid phase. The operating temperature and pressure of the test pipes are controlled within the range of 24–44°C and 1–3 bar, respectively. Seven air-oil flow patterns are identified based on visualization results: stratified smooth, stratified wavy, annular, plug, slug, bubbly, and dispersed bubble flows. On analyzing 1043 data points from the experiment, this study explores the effects of total mass velocity, flow quality, pipe diameter, operating temperature, operating pressure, and oil type on the frictional pressure gradient. Particular attention is given to the variation of the frictional pressure gradient concerning operating pressure, and its relationship with total mass velocity, flow quality, and flow pattern is discussed. Additionally, the study examines predictions from 55 previous correlations against the current pressure drop data. The predictive capability of these correlations is evaluated for the entire dataset and its subsets, categorized by oil type, pipe diameter, operating pressure, flow condition, total mass velocity, flow quality, and flow pattern. Evaluation metrics include mean absolute errors and the proportions of data points within 30% and 50% of absolute error. In addition, average and standard deviation values are calculated for each dataset to provide a comprehensive assessment.
... Generally, P min decreases with an increasing nozzle diameter. A slight difference between the experimental and calculated values of P min is sometimes observed due to pressure drop in the nozzle [90]. Meanwhile, a printing speed-dependent shear rate (γ • ) is induced at the nozzle tip during the extrusion of ink and can be calculated using the following equation (4) [91,92]: ...
Alumina (Al2O3) ceramics are one of the most widely employed advanced ceramics by industries. However, traditional forming methods have not been able to meet the demands of fine shape design and high-precision fabrication for advanced functional applications. 3D printing technologies are progressively gaining consideration in many manufacturing sectors for their ability of designing complex shapes and customized parts. Extrusion-based 3D printing technology, known as direct ink writing (DIW), is an adaptable, simple, and eco-friendly forming process and amongst the most used for ceramics. In the last several years, significant advancements have been made in alumina ceramics with complex designs by the DIW forming technique. This review presents recent progresses in creating dense and porous alumina ceramics using DIW. It provides a detailed description of printable ink formulation strategies and their effects on the sinterability of dense and porous alumina shapes. Ink composition and printing parameter effects on the final properties of DIW alumina are discussed. Concurrently, key ink rheology and post-processing parameters for desired alumina shapes are identified. The review also provides a pathway to overcome the technical challenges in achieving a high density or lightweight alumina monolith by DIW.
... Computational fluid dynamics (CFD) tools were developed to overcome those difficulties for both internal and external fluid flows (Hamad et al., 2017;Wei et al., 2018;Yu et al., 2010;Zambrano et al., 2017). Numerical investigations are becoming more attractive nowadays due to the flexibility and accuracy in the prediction of results. ...
Heavy oil and water dispersed flows in a 0.0254 m, 0.0381 m, 0.0508 m ID horizontal pipelines (Pipeline length = 2.5 m) were investigated experimentally and numerically (at steady state) without and with additives by varying the temperature from 25 °C to 50 °C by considering power law (i.e., for emulsion) rheological behavior. The development of boundary layer, pressure drop, velocity profile, boundary layer thickness, and wall shear were discussed in these numerical investigations without and with water, ML (i.e., a natural extract from Madhuca Longifolia), and PS (i.e., potato starch) via pipeline transportation of heavy oil. The pressure drops in the numerical simulations were compared with the available experimental results and found in qualitative agreement (i.e., max error ±7%). The pressure drop from the inlet to the outlet was decreased with an upsurge in the concentration of bio-additives in the aqueous phase of the heavy oil emulsion and temperature. The development of the boundary layer was significantly varied after adding water and bio-additives to the heavy oil. The ratio of boundary layer thickness and pipe length is reduced by increasing the additive's temperature and concentration in the heavy oil-water flows. Furthermore, the reduction in wall shear occurred after efficiently adding water and bio-additives to the heavy oil during transportation. The comparative studies also carried out between the influence of additives on the hydrodynamic parameter. The bio-additives (ML and PS) in the aqueous phase improve the hydrodynamics of heavy oil flow in the pipeline. Natural extract ML improves the hydrodynamics of heavy oil flow through the pipeline than potato starch. The application of numerical investigations can significantly enhance understanding the hydrodynamics of the heavy oil/emulsion's transportation via pipelines with greater accuracy for complex pipeline configurations.
... Its practical importance to industry coupled with the comparative ease with which it lends itself to analytical deductions has made this flow regime the focus of extensive investigations both experimentally and analytically [2]. Liquid holdup and pressure gradient are two important flow parameters also used to characterize multiphase flow systems, including annular flow, in pipes [3]. Variation of flow conditions such as liquid viscosity significantly impact these flow characteristics [4]. ...
Proper selection and application of interfacial friction factor correlations has a significant impact on prediction of key flow characteristics in gas–liquid two-phase flows. In this study, experimental investigation of gas–liquid flow in a vertical pipeline with internal diameter of 0.060 m is presented. Air and oil (with viscosities ranging from 100–200 mPa s) were used as gas and liquid phases, respectively. Superficial velocities of air ranging from 22.37 to 59.06 m/s and oil ranging from 0.05 to 0.16 m/s were used as a test matrix during the experimental campaign. The influence of estimates obtained from nine interfacial friction factor models on the accuracy of predicting pressure gradient, film thickness and gas void fraction was investigated by utilising a two-fluid model. Results obtained indicate that at liquid viscosity of 100 mPa s, the interfacial friction factor correlation proposed by Belt et al. (2009) performed best for pressure gradient prediction while the Moeck (1970) correlation provided the best prediction of pressure gradient at the liquid viscosity of 200 mPa s. In general, these results indicate that the two-fluid model can accurately predict the flow characteristics for liquid viscosities used in this study when appropriate interfacial friction factor correlations are implemented.
... Pressure drops have been analysed by some researchers in the previous years for the air-cooled condenser, turbine used for solar chimney power plant, turbine used for hybrid power plant and for the boiler [31][32][33][34]. It has also been investigated for the single phase turbulent flow in bend pipe, for the horizontal pipes with different diameters and for the vertical, spiral, d-type and helical corrugated pipes at different conditions with various parameters [35][36][37][38][39][40]. During this research work, power outputs and heat rates have been found at different enthalpy/temperature drop conditions through the pipelines. ...
In this research work, the effects of enthalpy/temperature drops in various pipelines on the performance of coal-fired thermal power plant have been analysed. Power outputs, heat rates, entropy generation rates, entropy generation numbers, exergy destruction rates, effectiveness, entransy dissipation rates, entransy dissipation-based thermal resistances and entransy dissipation numbers have been analysed for various components of the power plant at different enthalpy/temperature drops. Percentage changes (i.e. increments/decrements) in different parameters have also been calculated for a finite range of thermodynamic property drops. This analytical work can be concluded as: Maximum exergy destruction and entropy generation rates have been found for the boiler as 221,051.3 kW and 729.54 kW/K, respectively, at 100% load. The maximum energy rate has been converted in the intermediate-pressure steam turbine as 57,956.21 kW at 100%. Minimum exergy destruction and entropy generation rates have been obtained for low-pressure turbine as 5059.25 kW and 16.69 kW/K, respectively. It has also been found exergy destruction and entropy generation rates increase with enthalpy drop. Percentage increments in the exergy destruction and entropy generation rates also increase with enthalpy drop. Several recommendations have been given to the improvement of the plant outputs; maximum energy is converted in intermediate-pressure turbine so number of stages should be increased as compared to other steam turbines. Power plant should be operated on full load condition. Extraction pipelines should be properly insulated and better insulated pipe material should be used for the pipelines. Performance of feed water heaters can also be increased by preheating arrangement, i.e. solar water heaters.
... Kerugian minor adalah kerugian tekanan aliran fluida yang diakibatkan karena adanya sambungan pada sistem pipa (fitting) atau katup (elbow), saringan (strainer), percabangan (tee), loo pada bagian masuk dan keluar sistem pemipaan, pembesaran pipa (expansion), pengecilan pipa (contraction) dan sebagainya, sedangkan kerugian mayor adalah kerugian yang terjadi akibat gesekan aliran fluida dengan dinding permukaan pipa yang memiliki tingkat koefisien Penelitian mengenai penurunan tekanan pada laju aliran fluida oleh peneliti sebelumnya masih jarang ditemukan. Penelitian terakhir yang dilakukan untuk menganalisis penurunan tekanan terletak pada pengaruh parameter dari ukuran dimensi sistem pipa, dimana diketahui bahwa penurunan tekanan yang diakibatkan oleh ukuran dimensi pipa mencapai persentase sebesar ± 20% (Hamad et al, 2017), sedangkan penurunan tekanan aliran udara yang diakibatkan oleh sambungan elbow dengan sudut 90 0 mencapai persentase sebesar 11 % sampai dengan 13% (Dang et al, 2018). Penelitian ini dilakukan untuk menganalisis seberapa besar penurunan tekanan aliran udara yang ditimbulkan oleh penurunan tekanan minor (sambungan pipa) dan mayor (ukuran dimensi pipa) terhadap kualitas sistem pemipaan bertekanan yang digunakan . ...
... They indicated a need for further studies of polydisperse systems. Hamad et al. (2017) analysed the pressure drop a multi-phase fluid (water and air) flowing through pipes with different diameters. Also Sabiri and Comiti (1995) investigated the flow of non-Newtonian purely viscous fluids flowing through beds of various structure. ...
The results of analysis of airflow resistance through a porous stone accumulator bed are presented with studies conducted in laboratory and in a full-scale facility. The Darcy–Weisbach equation and Ergun's equation were used to determine the flow resistance coefficients. It was found that a simplification of the Ergun's equation by omitting the viscosity term did not result in a significant error in estimating the flow resistance. Dimensional analysis was applied to analyse the flow resistance in the full-scale facility and to determine the form and parameters of equation allowing a calculation of airflow resistance as a function of independent variables. The analysis showed a significant convergence between the friction factors and flow resistance calculated with the use of proposed equations and the values obtained from measurements. It is concluded that the following factors have the largest impact on the airflow resistance in order: bed particle diameter, followed by airflow velocity, effective section diameter and, to the same degree, layer height and bed mass.
... The pressure drop of a fluid is due to the variation of kinetic and potential energy of the fluid and that is due to friction on the walls of the flow channel (Hamad, et al, Z. 2017). The friction between the fluid particles in a pipe does cause a slight rise in fluid temperature as a result of the mechanical energy being converted to sensible thermal energy. ...
The form of transportation of energy from the sources to the consumers is the concern of the researchers across the world, this is due to the consequences upon the failures. Some of these failures causing economical losses and environmental damages. Both are worth to be investigated and studied to reduce the risks and losses. In this paper the effects of cracks in pipelines has been investigated, it is found that the crack is causing the decrease in pressure. Several pipes were used in the experiment, one without crack and the rest with different crack size. The pressure drop in the area around the crack (named crack zone) was bigger in the up and down stream zones. Computational fluid dynamics CFD package ANSIS (Fluent) was used in the analysis and the results presented. Because the fluid used in the research is crude oil, so the paper is mainly for the benefit of the oil and gas industries and the pipeline designers and manufacturers.
... It can be incurred from Fig. 2 (a) that the flow velocity near the inlet and the outlet is less but through the honey comb channel and the anode chamber is very high. Similar type of result was obtained by Hamad et al. [20], where they estimated the effects of various pipe diameters on fluid flow velocity. They observed that the pipe with 12 mm diameter had the maximum flow velocity of 0.5623 m/s which was almost 50e53% higher than that of the other two pipes. ...
Power crisis, global warming and various environmental issues have constantly emphasized researchers to discover sustainable and environmental-friendly alternative energy resources. Bio-electrochemical systems, significantly microbial fuel cells (MFCs) can harvest bioenergy from organic wastes and treat them simultaneously. Flow parameter investigation has been conducted in innovative flow straightener implemented honey comb MFCs (HCMFCs) in the current research study. The impacts of flow channel diameter on the performance of the HCMFCs operated in recirculation batch mode have been estimated in the current study. Three different diameters like 0.4 cm, 0.7 cm and 1 cm are used in three reactors as HCMFC1, HCMFC 2 and HCMFC 3 respectively along with a control reactor devoid of flow straighteners. Numerical simulation models are presented for reactor performance portrayal. The power performance is analyzed by Nyquist plots, polarization curves, power density curves and equivalent circuits. Result justification is accomplished by anode biofilm thickness analysis using scanning electron microscope. HCMFC 2 showcased the best performance by achieving a voltage generation of 0.55 V, current density of 5300 mA/m², power density of 430 mW/m², organic content removal of 97.6%, reduced internal resistance and with the thickest anode biofilm. These innovative reactors will effectively enhance research and provide great prospects for future applications.
... The experimental procedure was validated with pressure drop measurements of single-phase water flow that were used to calculate the friction factor and compare with the predicted by Blasius equation works also reported that the two-phase pressure drop decreases as the internal pipe diameter increases [48,49]. It is observed that the two-phase pressure drop increases with increasing cavity width for the different internal pipe diameters. ...
Corrugated pipes have regularly shaped and spaced cavities on their internal walls that can induce dynamic changes in the flow, such as pressure drop increases. Petroleum offshore production pipelines are an example of an industrial application of corrugated pipes, known as flexible lines. From the hydrodynamic standpoint, slug flow is reckoned as the most common flow pattern inside those lines. A number of previous studies proposed correlations to predict two-phase flow pressure drops in smooth pipes. However, limited researches have evaluated the pressure drops associated to liquid-gas slug flow in corrugated pipes. In this work, experiments were carried out to analyze the pressure drops in horizontal air-water slug flow under different configurations of corrugated pipes. The tests were performed in three different internal diameters of corrugated pipe (26, 40 and 50 mm) with different cavity widths (1.2, 1.6 and 2.0 mm). The effects of the internal diameters and the cavity widths on slug flow pressure drop were analyzed. Results demonstrated that the pressure drop increases with increasing the cavity widths. The experimental data were fitted and a pressure drop correlation using the concept of multiplier factor was proposed. Comparisons between predictions and experimental data showed 10% accuracy.
... Unfortunately, Sairson and Wongwises [98]do not provide further discussions concerning this behavior. On the other hand, Hamad et al. [99] and Lu et al. [100] experimentally investigated the pressure drop for air-water flow in channels with internal diameter larger than 12 and 38 mm, respectively, hence for conventional sized channels. According to these studies, the pressure drop trend is unaffected by flow pattern transition from bubbles to intermittent flow. ...
This paper presents a broad study on gas-liquid flow in inclined channels with rectangular cross section. Experimental data are presented for flow patterns, pressure drop and bubble shape during air-water flows for channel inclinations ranging from −90° to +90° relative to the horizontal plane, and channel axial rotations of 0, 45 and 60°. The test section is 6.0 mm deep, 6.5 mm wide, and 1.2 m long. Experiments were performed for mass velocities ranging from 90 to 760 kg/m²s, corresponding to gas and liquid superficial velocities ranging from 0.09 to 19.4 m/s, and from 0.1 to 0.76 m/s, respectively. Flow patterns were identified based on flow images captured with a high-speed video camera and on the k-means clustering method based on an analysis of pressure drop and optical signals. It was found that duct inclination and channel rotation affect the flow pattern transitions. Moreover, two-phase stratification effects were enhanced by rotating the channels, and the effect of channel rotation on pressure drop was found negligible. On the other hand, the channel inclination affects significantly the pressure drop, whereas gravitational pressure drop parcel was the main parcel of the total pressure drop for most of non-horizontal conditions. The influence of flow pattern transitions on the pressure drop was inferred based on changes of the pressure drop behavior.
... They reported that the void fraction was well correlated by the drift flux model with the existing correlation for the distribution parameter, which was about 1.35, the frictional pressure loss was found to be well predicted by the Chisholm-Laird correlation, and the parameter C depends on the hydraulic diameter, decreasing from 21 to 0 as the hydraulic diameter decreases from 10 to 0.1 mm. Hamad et al. [5] compared their results of pressure drop of gas-liquid flow in horizontal pipes of different diameters from 12.7 to 25.4 mm with a number of empirical models. They found the drift-flux model and homogenous model were the most suitable models for pressure drop prediction compared with another models, such as Lockhart-Martinelli and Friedel model. ...
Aiming at developing a more common method for predicting two-phase flow pressure drop for small channels, experiments on frictional pressure drop of air-water flow in a vertical narrow rectangular duct with a cross-section of 40 mm by 1.6 mm were conducted at atmospheric pressure. The mass flow rates of air and water covered the ranges from 0.03 to 12.5 kg/h and from 19 to 903 kg/h, respectively. It was found that the two-phase flow can be divided into three regions according to the liquid only Reynolds number, by which a modified Chisholm two-phase multiplier was proposed for predicting frictional pressure drop. Some leading correlations for predicting two-phase flow pressure drop were compared with the new correlation against current experimental data, the latter had and a mean deviation of 7.2%, showing a better agreement with the experimental results.
This article analyzes the adaptability of the gathering and transportation pipelines of M well area from W shale gas field in different production stages. The pipelines are divided into three categories according to the degrees of being influenced by new pipelines. Typical pipeline transportation adaptability is analyzed, and improvement measures are proposed. The results show that the proportion of pipelines whose adaptability levels are above “medium” is 100%, 56%, and 39% in the early, middle, and late stages of production, respectively, which shows a decreasing trend. The adaptability level of the first type of pipeline decreases with the decrease of pipeline flow rate. Building a new pipeline can improve the adaptability level of the second type of pipeline downstream of the pipeline network. Building two or more pipelines can maintain the adaptability level of the third type of pipeline downstream of the pipeline network at “high” or “relatively high”. In response to the reduced adaptability in the middle and late stages, pigging and boosting simulations are conducted. A pigging plan and a rolling “platform boosting in coordination with centralized boosting” plan is developed, resulting in a 92% and 87% increase in transport efficiency in the middle and late stages, respectively. It was also demonstrated that cleaning can be one of the measures to enhance gas production. This article proposes the concept of adaptability analysis for different production stages in shale gas fields for the first time, and proposes reasonable measures to improve the adaptability of shale gas pipeline networks.
Accurate prediction of two-phase parameters is essential for the development, operation and safety of nuclear power plants. In this paper, the ANN-based model has been developed, implemented with PDE (Partial Differential Equation) solver in case study of two-phase frictional pressure drop prediction.
To solve the problem of high-concentration coal-water slurry (CWS) pipeline transportation with large resistance, it was proposed to inject gas into the coal-water slurry pipeline and adopt gas film to reduce the resistance loss of the pipeline. For Bingham non-Newtonian fluid CWS, based on the volume of fluid (VOF) multiphase flow model, the effects of the key parameters of the gas pipe on the drag coefficient were analyzed through numerical simulation, and the influence of genetic aggregation response surface model and nonlinear programming by quadratic Lagrangian (NLPQL) algorithm were combined to perform surrogate-assisted optimization. The results show that the gas pumping inlet into the CWS pipeline can effectively reduce the wall shear stress, the gas velocity and the diameter of the gas pipe have a significant effect on the pipeline resistance coefficient. In addition, increasing the gas velocity and the diameter of the gas pipe can reduce the resistance coefficient, while the pipeline resistance coefficient is almost unaffected by the angle of the gas pipe. Taking the minimization of the resistance coefficient as the objective function, a set of gas pipe parameters is obtained. After optimization the resistance coefficient of the pipeline decreased by 0.0207, and the drag reduction rate is improved by 16.90%. The research results provide theoretical guidance for the mechanism and structural optimization of gas injection for drag reduction in high-concentration CWS pipelines.
This study focuses on the frictional pressure drop in gas-liquid two-phase flow, characterized by nonlinear behavior under various flow conditions due to complex two-phase phenomena. The experimental investigation involves an air-oil mixture flowing through horizontal pipes with diameters of 20 mm and 40 mm, aiming to observe the flow patterns and quantify the pressure drop. Two oils with different thermophysical properties are used as the liquid phase. The operating temperature and pressure of the test pipes are controlled within the range of 24–44°C and 1–3 bar, respectively. Seven air-oil flow patterns are identified based on visualization results: stratified smooth, stratified wavy, annular, plug, slug, bubbly, and dispersed bubble flows. On analyzing 1043 data points from the experiment, this study explores the effects of total mass velocity, flow quality, pipe diameter, operating temperature, operating pressure, and oil type on the frictional pressure gradient. Particular attention is given to the variation of the frictional pressure gradient concerning operating pressure, and its relationship with total mass velocity, flow quality, and flow pattern is discussed. Additionally, the study examines predictions from 55 previous correlations against the current pressure drop data. The predictive capability of these correlations is evaluated for the entire dataset and its subsets, categorized by oil type, pipe diameter, operating pressure, flow condition, total mass velocity, flow quality, and flow pattern. Evaluation metrics include mean absolute errors and the proportions of data points within 30% and 50% of absolute error. In addition, average and standard deviation values are calculated for each dataset to provide a comprehensive assessment.
The nanoparticle (NP) exhibits numerous distinctive and extraordinary properties than micron level and up. The inclusion of NP effects in the rheological and densification behavior of extrusion-based (direct ink writing (DIW)) inks has been extensively investigated. The aqueous-based alumina-silica inks were first designed using waste rice husk ash (RHA) derived nano-silica (NS) (0–10 wt%) and found that the solid-to-liquid ratio reduces continuously with NS addition for printable rheology. For functionalization of NS, dispersant requirement is increased that improve the solids loading of inks. Second, the optimized inks are printed via DIW technique and sintered at a temperature of 1400–1650 °C. The NS has remarkably enhanced the shrinkage, density, and morphology of sintered DIW specimens and 7.5 wt% RHA NS reduces the sintering temperature ∼150 °C. Incorporating NP in the 3D printing ink is a clean approach to filling pores generated by binder-burnout and fabricating a dense ceramic at a low temperature.
Nanoparticles (NPs) show many unique and advanced behaviors compared to micron-sized particles and above. The effect of NPs on the rheological and sintering nature of direct ink writing (DIW) [extrusion-based three-dimensional (3D) printing] inks has been comprehensively studied. The inks were first formulated through particle size grading of microalumina and nanoalumina (NA) with aqueous-based solvents, and it was found that the solid volume in ink increases up to a certain volume of NA (2%) inclusion due to the change in friction mechanism between particles. Meanwhile, the presence of high volumes of NA (≥3 vol %) reduces solid-loading in ink due to agglomeration of NPs for printable rheology. Second, different NA (0-5 vol %)-containing optimized rheological inks were printed by DIW and sintered at temperatures of 1300-1600 °C. Higher solid-loading ink retaining 2 vol % NA shows low volume shrinkage, and 5 vol % NA-containing ink reaches 97% density at temperatures as low as 100 °C than without NA ink. Including NPs in the ceramic 3D printing technology decreases the use of organic contents (reduce greenhouse effect) and also effectively reduces the shrinkage and fabricates a dense printed structure by eliminating binder-burnout generated pores at a low temperature (energy conservation).
Two-phase flow is widely occurring in various engineering entities ranging from power plants, petroleum refineries to process industries. The potential to precisely predicts the drop in two-phase flow pressure is crucial and varies depending on the number of variables such as phase mass flux, channel orientation, channel cross-section, and channel size. The work gives an investigational examination of adiabatic air–water two-phase flow in minichannels. Horizontally kept circular transparent tubes of 1.0, 1.5, 2.0, 2.5, and 3.0 mm diameter were used for experimentation. Variation of mass flux used was from 307 to 7883 kg/m2 s for these experiments. Some of the available correlations from open literature were compared with experimental pressure drop data. The assessment revealed that known correlations are insufficient to infer experimental data. A new empirical correlation encompassing fluid properties was built based on evidence from trials. The new correlation made a decent fit to the present experimental results. It was noticed that majority of the data is lying within the ±35% error range.KeywordsAdiabatic flowAir–water flowTwo-phase flowPressure dropMinichannelsEmpirical correlationExperimental studyCircular tubes
The possibility of removing the export gas compressor from the central process facilities (CPF) in a gas project and enlarging the size of the gas export pipeline from the CPF to reduce the total capital expenditure (CAPEX) and operating expenditure (OPEX) is evaluated. Adding the export gas compressor to the CPF will increase the carbon footprint of the CPF, the power requirements of the CPF, and the emission of greenhouse gases. The CPF equipment would be designed for a lower operating pressure which leads to larger equipment sizes. PIPESIM and HYSYS software were used to simulate the CPF and different sizes of the export gas pipeline. With an export gas pipeline size smaller than 24”, an export gas compressor is required for the CPF, and as the pipeline size is reduced, the compressor power requirement will rise. CAPEX and OPEX comparisons were conducted between adding the export gas compressor or enlarge the size of the export gas pipeline. CAPEX and OPEX decline with larger pipeline size.
Microbial fuel cells (MFCs) are recognized as a state‐of‐the‐art technology that generates biochemical energy and converts it to electrical energy. MFCs include a series of metabolizing organic material from wastewater and allow its treatment while providing the opportunity to generate electricity. It is to be noted that the buffer used commonly in MFCs is relatively costly and quantified to have environmental impacts when applied in commercial wastewater treatment. To address the concern related to the buffer, this work proposes to evaluate a geometrical design of honeycomb whose inner diameters (0.4, 0.7, 1.2 cm) and lengths (2.5, 5 cm) were selected to replace the buffer. With the introduction of the honeycomb design, the study also aims to investigate its effect on the performance of recirculation within the MFCs. This is then evaluated under the optimal operational flow rate and pH level, which were already established by previous studies. The results have revealed that the optimal geometry of the honeycomb consists of a dimension with an inner diameter of 1.2 cm and a length of 5 cm. This combination of inner diameter and length of the honeycomb has yielded the highest power density for the MFC at 491 mW m−2 when compared with the other cases. The findings of this study will be useful for the development of a cost‐effective and environmentally friendly MFC when applied in commercial wastewater treatment in the future. Microbial fuel cells (MFCs) are recognized as a state‐of‐the‐art technology that generates biochemical energy and converts it to electrical energy. MFCs include a series of metabolizing organic material from wastewater and allow its treatment while providing the opportunity to generate electricity.
In the past few years, several techniques and approaches have been developed by researchers for the ocean survey. An autonomous underwater vehicle primarily known as the glider is vastly used for oceanographic study and survey. With the help of these vehicles now it possible to have a study on the effects of pesticides, metal, biological toxins, or chemicals on the living organisms of the sea. Additionally, monitoring of threats such as biological weapons, radioactive leakage, and detection of mines is a very important parameter for keeping safety in check. Considering these parameters autonomous vehicles primarily known as glider are vastly used by oceanographers as they are relatively inexpensive, reusable, and have long mission durations. Such vehicle uses advanced sensors to perform automated monitoring and fast data acquisition. Since their inception in the 1980s, there have been considerable developments that have led to the augmentation of scientifically and commercially focused products. A comprehensive analysis of various underwater gliders and their working principle has been done here, emphasizing their architecture and working capabilities.
In the present study, the effect of polyacrylamide (PAM) addition as a drag-reducing agent on the hydraulic and heat transfer performance of water flow inside horizontal smooth circular pipes was investigated at different heat fluxes. One of the limitations of using solutions containing drag reducing agents (DRAs) is heat transfer reduction (HTR) properties of these substances. The effect of different hydraulic and thermal factors on this phenomenon has been less systematically investigated. In this study, a large number of experiments were conducted under different operating conditions including concentrations of 50, 100, 150 ppm of PAM, inner pipe diameters of 12.7, 19.05, 25.4 mm, applied heat fluxes to pipes including 11, 15, 19 kW/m2, and fluid flowrates at the range of 0.5–20 l/min to prepare laminar, transition, and turbulent flow regimes. The maximum percentage of drag reduction (%DR) obtained at the diameter of 12.7 mm, flowrate 20 l/min, concentration 150 ppm, and at zero-wall heat flux (adiabatic condition) by 50%. By applying heat flux, the%DR decreased. Results showed that the addition of the drag reducing polymer reduces the heat transfer but applying constant heat flux to the pipe decreases the effect of polymer on the percentage of heat transfer reduction (%HTR). The maximum%HTR of 44.5% was achieved at the flowrate of 0.5 l/min and the concentration of 150 ppm and the heat flux of 11 kW/m2. Increasing pipe diameter at all the heat fluxes and polymer concentrations, decreased%DR and%HTR.
The influence of sub-regimes of intermittent flow on the pressure drop has been investigated. Two-phase, air-water, flow experiments were conducted on 30 mm ID pipe. The superficial velocities of the working fluids were chosen to cover three sub-regimes: Plug flow, Less Aerated Slug flow (LAS flow) and Highly Aerated Slug flow (HAS flow). The analysis of the experimental data, including the data drawn from the literature showed that the pressure drop depends on the flow sub-regime. A new empirical correlation, based on the Lockhart-Martinelli approach, taking into account the nature of sub-regime was proposed. The present correlations, in comparison with the existing correlations, give the best results.
A high-pressure and large-diameter extraction borehole is used in coal mines due to lack of understanding of the mechanism of negative pressure in the process of gas extraction, which will lead to problems such as poor gas extraction and collapse of the borehole. In order to solve these problems, the flow and pressure distribution in the process of variable mass flow of gas drainage borehole were studied based on factors such as orifice pressure, bore diameter, and bore flow. Firstly, we built a testing platform for variable mass flow pressure distribution and established a variable mass flow energy model and pressure distribution model. Secondly, the correlation between pressure distribution and orifice pressure, borehole diameter, and borehole flow in the process of variable mass flow was calculated by combining laboratory testing with numerical calculations. Finally, the results showed that with the increase in borehole length, pressure, and flow exhibited a downward trend during the variable mass flow of the borehole. Additionally, the pressure distribution in the borehole had a negative exponential relationship with borehole pressure and the diameter of the borehole. The pressure distribution in the borehole had a power-exponential relationship with the gas flow. These research results will provide a reference for the selection of reasonable parameters.
Phosphorus is one of most produced radioisotopes at Center for Radioisotope and Radiopharmaceutical Technology – BATAN. This product is formed as phosphorus-32 (³²P) which is useful for industrial, agricultural, research and health field purposes. The radioisotope ³²P can be produced by extraction, dry distillation and precipitation method. In a dry distillation process of ³²P, a Sulphur which is after irradiated at Multipurpose Reactor G. A. Siwabessy is heated up until its melting and boiling point is achieved. This research was carried out in a radioisotope and radiopharmaceutical production laboratory, to find out how much pipe openings gas valve the nitrogen ultra-high purity (UHP), the proper airflow pattern, and the pressure drop to produce high purity ³²P radioisotope products. For this research, measurement and calculation conducted using valve opening degree variation at 0°, 30°, 45°, 50°, 55°, 60°, 90°, 180° and 270° with gas nitrogen UHP. Based on the results of research, it was found that the right Nitrogen UHP gas pipe openings were 45° to 50°, with the Reynold Number in stage 2 being 240 - 313 which is a laminar flow pattern. Based on calculations, the total pressure drop form all distillation stages for openings gas valve 45° to 50° is 7 - 9 Pascal. The average ³²P radioisotope purity obtained before determination and measurement of flow patterns, openings gas valve nitrogen UHP, and proper pressure drop, was 80.4% and after determination and measurement increased to 99.9%.
This study investigates the effect of pipe diameter on pressure drop with the same diameter ratio, similar pressure-sampling position and throat length of long-throat Venturi. Considering the factors including the void fraction, the friction between the two phases and the entrainment in the gas core, the one-dimensional momentum equation for gas has been solved in the axial direction of long-throat Venturi. A novel void fraction model is established, by considering the effects of dryness and gas-liquid density ratio, then predicting the distribution of wet gas static pressure between the two pressure tapings of the long-throat Venturi. The comparison between the values predicted by the model and those measured experimentally reveals that all the relative deviations of the predicted points by the modified model were within ±15%. In the same entrance conditions, the effect of pipe diameter on pressure drop in long-throat Venturi is similar.
Pressure drop of bubbly flow is a widely used parameter in petroleum industry. The energy dissipation rate is induced by three factors, including wall resistance, bubble breakup and coalescence, which is studied here from the perspective of the macroscopic flow and microscopic bubbles. This work details a model using the principle of energy conservation to clarify the mechanism of the pressure drop for turbulent bubbly flow in horizontal pipes. The model was validated via a comparison with experimental data of horizontal bubbly flow collected from nine previous studies with 200 points. Most of the errors are within ±20%. The proportions of pressure drop induced by wall resistance, bubble breakup and coalescence were calculated by the model. The results indicate that the largest proportion is from wall resistance, followed by bubble coalescence, with bubble breakup having the smallest proportion. In addition, the trends of proportion induced by the three factors above are analyzed by increasing gas volume fraction and mixture viscosity. The results show that the proportion induced by wall resistance decreases with the increasing volume fraction of the gas, and increases with the increasing mixture viscosity. The proportions induced by the bubble breakup and coalescence in the opposite case.
A simple semitheoretical method for calculating two-phase frictional pressure gradient in horizontal circular pipes using asymptotic analysis to develop a robust compact model is presented. Two-phase frictional pressure gradient is expressed in terms of the asymptotic single-phase frictional pressure gradients for liquid and gas flowing alone. The proposed model can be transformed into either a two-phase frictional multiplier for liquid flowing alone (ϕl²) or two-phase frictional multiplier for gas flowing alone (ϕg²) as a function of the Lockhart-Martinelli parameter, X. Single-phase friction factors are calculated using the Churchill model which allows for prediction over the full range of laminar-transition-turbulent regions and allows for pipe roughness effects. The proposed model is compared against published data to show the asymptotic behavior. Comparison with other existing correlations for two-phase frictional pressure gradient such as the Chisholm correlation, the Friedel correlation, and the Müller-Steinhagen and Heck correlation, is also presented. Comparison with experimental data for both ϕl and ϕl versus X is also presented. At the end of the paper, the present asymptotic model is also extended to minichannels and microchannels.
The reliable predictions of liquid holdup and pressure drop are essential for pipeline design in oil and gas industry. In this study, the drift-flux approach is utilized to calculate liquid holdups. This approach has been widely used in formulation of the basic equations for multiphase flow in pipelines. Most of the drift-flux models have been developed on an empirical basis from the experimental data. Even though, previous studies showed that these models can be applied to different flow pattern and pipe inclination, when the distribution parameter is flow pattern dependent. They are limited to a set of fluid properties, pipe geometries and operational conditions. The objective of this study is to develop a new drift-flux closure relationship for prediction of liquid holdups in pipes that can be easily applied to a wide range of flow conditions. The developed correlation is compared with nine available correlations from literatures, and validated using the TUFFP (Fluid Flow Projects of University of Tulsa) experimental datasets and OLGA (OiL and GAs simulator supplied by SPTgroup) steady-state synthetic data generated by OLGA Multiphase Toolkit. The developed correlation performs better in predicting liquid holdups than the available correlations for a wide range of flow conditions.
A simple approach for calculating the interfacial component of frictional pressure gradient in two-phase flow at microscales is presented. This approach is developed using superposition of three pressure gradients: single-phase liquid, single-phase gas, and interfacial pressure gradient. The proposed model can be transformed in two different ways: first, two-phase interfacial multiplier for liquid flowing alone () as a function of two-phase frictional multiplier for liquid flowing alone () and the Lockhart-Martinelli parameter, X, and, second, two-phase interfacial multiplier for gas flowing alone (ϕg,i2) as a function of two-phase frictional multiplier for gas flowing alone (ϕg2) and the Lockhart-Martinelli parameter, X. This proposed model allows for the interfacial pressure gradient to be easily modeled. Comparisons of the proposed model with experimental data for microchannels and minichannels and existing correlations for both ϕl and ϕg versus X are presented.
The calculation of frictional pressure drop for two-phase flow in pipes is required by a variety of design practices. In the past six decades, many correlations for two-phase frictional pressure drop were proposed, and some evaluations were provided. However, both the correlations and the experimental data included in the existing evaluation literature are limited, which makes the evaluation results inconsistent and inaccurate. This work conducts a comprehensive survey of correlations and experimental investigations of two-phase frictional pressure drop. There are 29 correlations reviewed, and 3480 experimental data points are obtained from the open literature, with the experimental range of hydraulic diameters from 0.0695 to 14 mm, and mass flux from 8 to 6000 kg/m2 s. The reviewed correlations are evaluated against the experimental data, and two correlations which can present the most agreeable predictions are found.
In this tutorial the fundamentals of non- boiling heat transfer in two-phase two- component gas-liquid flow in pipes are presented. The techniques used for the determination of the different gas-liquid flow patt erns (flow regimes) in vertical, horizontal, and inclined pipes are reviewed. The va lidity and limitations of the numerous heat transfer correlations that have been published in the literature over the past 50 years are discussed. The extensive results of the recent developments in the non-boiling two- phase heat transfer in air-water flow in horizontal and inclined pipes conducted at Oklahoma State University's Heat Transfer Laborator y are presented. Practical heat transfer correlations for a variety of gas-liquid f low patterns and pipe inclination angles are recommended. Keywords . Two-phase flow, gas-liquid flow, heat transfer, h orizontal flow, upward- inclined flow
Empirical correlations were tested against reliable two phase pipe flow data for the prediction of pressure drop. Correlations are recommended for the prediction with stratified and annular type flows. When these correlations were adapted to three phase gas–water–oil pipe flow in general they predicted for intermittent slug type flows. Momentum balance models could not be successfully adapted to the prediction of pipe three phase pressure drop.
Two-phase flow of gases and liquids or vapors and liquids in pipes, channels, equipment, etc. is frequently encountered in industry and has been studied intensively for many years. The reliable prediction of pressure drop in two-phase flow is thereby an important aim. Because of the complexity of these types of flow, empirical or semiempirical relationships are only of limited reliability and pressure drops predicted using leading methods may differ by up to 100%. In order to improve prediction methods, this work presents an experimental and analytical investigation of two-phase pressure drops during evaporation in horizontal tubes. The goal of the experimental part was to obtain accurate two-phase pressure drop values over a wide range of experimental conditions. The existing LTCM intube refrigerant test loop has been modified and adapted to the new test conditions and measurement methods. Two new test sections have been also implemented into the modified test rig. The new test section consists of two zones: diabatic and adiabatic. This configuration allows tests to be run that obtain experimental two-phase pressure drop values under diabatic and adiabatic conditions simultaneously. The experimental campaign acquired 2543 experimental two-phase pressure drop values. Based on a comprehensive state-of-the-art review and comparison with two-phase frictional pressure drop prediction methods, it is proven that none of these methods were able to accurately, reliably predict the present experimental values. In the second part of this work, an analytical study was undertaken in order to develop a new two-phase frictional prediction method. It has been shown in the literature that the so called "phenomenological approach" tends to provide more accurate and realistic predictions as the interfacial structure between the phases is taken into account. Based on that, a phenomenological flow pattern approach was chosen in the present study. The recent Wojtan-Ursenbacher-Thome [155] map was chosen to provide the corresponding interfacial structure. The new model treats each flow regime (i.e. interfacial structure) separately and then ensures a smooth transition in between, being in agreement with the experimental observations. Another important feature of the proposed model is that it matches the correct limits at x = 0 (single-phase liquid flow) and x = 1 (single-phase gas flow). Based on a statistically comparison, it is concluded that the new two-phase frictional pressure drop model based on flow pattern map successfully predicts the new experimental data. The present work completes the fourth basic step in LTCM's flow pattern based work on two-phase flow and heat transfer inside horizontal round tubes: (i) generalized flow pattern map, (ii) flow boiling heat transfer model, (iii) convective condensation model and (iv) two-phase frictional pressure drop model. Les écoulements biphasiques liquide/gaz ou liquide/vapeur en tubes, canaux ou dans différentes géométries sont un problème fréquemment rencontré dans les applications industrielles et ont été largement étudiés ces dernières années. De par leur importance pratique, la prédiction des pertes de charges des écoulements biphasiques doit être précise. La complexité de ces types d'écoulements fait que les relations empiriques ou semi-empiriques usuelles sont peu précises et leurs prédictions peuvent différer parfois de 100%. Ce travail présente une investigation expérimentale et analytique des pertes de charges biphasiques durant l'évaporation en tubes horizontaux en vue d'en améliorer les méthodes de prédiction. La campagne expérimentale a permis d'obtenir une base de données élargie et fiable de pertes de charges biphasiques. Une boucle de test existante au LTCM pour l'étude des réfrigérants dans des tubes a été modifiée et adaptée aux nouvelles conditions de test et méthodes de mesures. Deux nouvelles sections de tests ont été implantées dans la boucle modifiée. Elles sont composées de deux zones : l'une adiabatique et l'autre non adiabatique. Cette configuration permet d'étudier simultanément les pertes de charges biphasiques en zone adiabatique et en zone non adiabatique. La campagne expérimentale a permis d'obtenir 2543 valeurs de pertes de charges biphasiques. Une étude bibliographique approfondie et une comparaison avec différentes méthodes de prédiction de pertes de charges biphasiques ont montré qu'aucune de ces méthodes ne permettait une prédiction précise et fiable des ces résultats expérimentaux. Dans la seconde partie de ce travail, une étude analytique a été réalisée afin de développer une nouvelle méthode de prédiction des pertes de charges biphasiques par frottement. Une approche phénoménologique a été adoptée dans cette étude car il a été démontré dans la littérature qu'elle permet des prédictions plus réalistes et plus précises en prenant en compte la structure de l'interface entre les phases. Cette structure de l'interface entre les phases a été obtenue en se basant sur la carte d'écoulement de Wojtan-Ursenbacher-Thome [155]. Ainsi le nouveau modèle traite chaque type d'écoulement séparément et assure également des transitions correctes, en accord avec les observations expérimentales. Une autre innovation importante de ce nouveau modèle est qu'il prend correctement en compte les deux limites a x = 0 (écoulement monophasique liquide) et x = 1 (écoulement monophasique gazeux). Une étude statistique a permis de conclure que ce nouveau modèle basé sur les cartes d'écoulements prédit avec succès les résultats expérimentaux. Ainsi cette étude complète la démarche en 4 étapes du LTCM concernant les écoulements biphasiques et les transferts de chaleur internes dans des tubes horizontaux circulaires: (i) carte d'écoulement non adiabatique généralisée, (ii) modèle de transfert de chaleur en ébullition, (iii) modèle de transfert de chaleur en condensation et (iv) modèle de pertes de charges biphasiques.
The dynamics of high Reynolds number-dispersed two-phase flow strongly depends on the wakes generated behind the moving bodies that constitute the dispersed phase. The length of these wakes is considerably reduced compared with those developing behind isolated bodies. In this paper, this wake attenuation is studied from several complementary experimental investigations with the aim of determining how it depends on the body Reynolds number and the volume fraction alpha. It is first shown that the wakes inside a homogeneous swarm of rising bubbles decay exponentially with a characteristic length that scales as the ratio of the bubble diameter d to the drag coefficient Cd, and surprisingly does not depend on alpha for 10(-2)<or=alpha<or=10(-1). The attenuation of the wakes in a fixed array of spheres randomly distributed in space (alpha=2 x 10(-2)) is observed to be stronger than that of the wake of an isolated sphere in a turbulent incident flow, but similar to that of bubbles within a homogeneous swarm. It thus appears that the wakes in dispersed two-phase flows are controlled by multi-body interactions, which cause a much faster decay than turbulent fluctuations having the same energy and integral length scale. Decomposition of velocity fluctuations into a contribution related to temporal variations and that associated to the random character of the body positions is proposed as a perspective for studying the mechanisms responsible for multi-body interactions.
In this study, a note on mixture density using the Shannak definition of the Froude number is presented (Shannak, B., 2009, “Dimensionless Numbers for Two-Phase and Multiphase Flow,” Proceedings of the International Conference on Applications and Design in Mechanical Engineering (ICADME), Penang, Malaysia, Oct. 11–13, 2009). From the definition of the two-phase Froude number, an expression of the two-phase density is obtained. The definition of the two-phase density can be used to compute the two-phase frictional pressure gradient using the homogeneous modeling approach in circular pipes, minichannels, and microchannels. We cannot have gas density ≤ two-phase density ≤ liquid density for 0 ≤ mass quality ≤ 1. Therefore, attention must be paid when using the obtained expression of the two-phase density in this note at any x value.
Zeotropic mixtures are widely used in mixed refrigerant Joule–Thomson cryocoolers for various applications such as cryoprobes. Within the Joule–Thomson cycle, multicomponent mixtures exist in a two-phase condition throughout a large portion of the system. Frictional pressure drop correlations for zeotropic refrigerants operating at these conditions are necessary for designers to optimize these systems; however, there are limited experimental data on the two-phase pressure drop of these mixtures available in the open literature.
This paper provides experimental data for the frictional pressure drop exhibited by a set of multicomponent zeotropic mixtures boiling in small channels over temperatures ranging from 100 K to room temperature along with the sensitivity of frictional pressure drop to parameters such as mass flux, pressure, tube diameter, and mixture composition. The measured data are compared to several pressure drop correlations available in the literature and the Awad and Muzychka (definition 1) correlation (Awad and Muzychka, 2008) was able to predict the frictional pressure drop over the range of experimental data considered, with an Absolute Average Deviation (AAD) of 17%. The second best correlation is Sun and Mishima (2009) with an AAD of 18%. In addition, the Cicchitti et al. (1959), Müller-Steinhagen and Heck (1986) and Mishima and Hibiki (1996) correlations also show reasonable agreement with the experimental data. Based on our data, the Awad and Muzychka (definition 1) (Awad and Muzychka, 2008) homogeneous model is recommended for prediction of pressure drop because this correlation agrees with 81% of our data with a relative absolute error lower than 25%.
New dimensionless friction pressure drop correlations are advocated both for horizontal and vertical upflow and for vertical downflow in unheated straight channels with circular, rectangular and annular cross sections. They incorporate all essential variables of the two phase flow as parameters and include the theoretical boundaries of single phase liquid and gas-vapor flow and of critical pressure conditions in single component mixtures. The predictive accuracy and the improvements are demonstrated comparison to rival methods using various characteristic error criteria and a new data bank, which at present embodies about 25 000 friction pressure drop measurements of various single and two component mixtures taken under widely varied test conditions. The proposed correlations are evidently better than other commonly accepted and recommended methods. They now allow a reproduction of the experimental results within the investigated range with an acceptable accuracy and reliability, which suffices for technical purposes. It is anticipated that moderate and adequate extrapolations beyond the scope of the data used and to conduits with other flow geometries are possible. (A)
This work presents an approximate Riemann solver to the transient isothermal drift flux model. The set of equations constitutes a non-linear hyperbolic system of conservation laws in one space dimension. The elements of the Jacobian matrix A are expressed through exact analytical expressions. It is also proposed a simplified form of A considering the square of the gas to liquid sound velocity ratio much lower than one. This approximation aims to express the eigenvalues through simpler algebraic expressions. A numerical method based on the Gudunov's fluxes is proposed employing an upwind and a high order scheme. The Roe linearization is applied to the simplified form of A. The proposed solver is validated against three benchmark solutions and two experimental pipe flow data.
The search for oil and gas continues to progress towards increasingly hostile environments. Environments such as found in deepwater preclude the ability to efficiently separate the fluid phases prior to export. As a result, multiphase transportation has become commonplace with systems being designed using integrated flow assurance techniques.
Additionally, pipelines that had been designed for single phase flow are now expected to cope with the transport of multiple phases. With the continuous variation in production, these pipelines tend to operate under both steady-state and transient conditions. The requirement to model these systems is, therefore, critical for adequate field development planning.
This paper will present a tutorial focusing on the complex analysis of multiphase flow in pipelines with an emphasis on the tools currently available for modeling purposes. The tools selected for use during the tutorial include Pipesim and OLGA.
The effect of introducing kerosene drops on turbulence of kerosene–water two-phase in a vertical pipe is
investigated experimentally. A hot-film and dual optical probes are used to measure the water velocity,
turbulence fluctuation, drop relative velocity, volume fraction and drop diameter. Experiments are performed
in a 78.8 mm diameter vertical pipe for four average water velocities of 0.11, 0.29, 0.44 and 0.77 m/s. The measurements were carried out for two area average volume fraction hai of 4.6% and 9.2% as well as for water single phase flow to investigate the effect of introducing kerosene drops on two-phase flow turbulence. The kerosene–water mixture was generated by adding the kerosene to constant flow rates of water. The results indicate that drops induced turbulence is a function of the ratio of the drop Reynolds number to the turbulence Reynolds number which decreased with higher water velocities. The results show that the Kolmogorov–Richardson scaling in the range of -�4.5/3 to -�6/3 for single phase flow which is replaced by �-6/3 to -�7/3 for two-phase flow. These values are less than �8/3 for air–water flow.
Cooling systems are needed for electronic devices in order to operate efficiently. Whereas the size of the equipment has decreased to the micro scale, research on the heat transfer characteristics in a microchannel heat sink is needed. In this work, we suggest that the segmented air–water flow can enhance the heat transfer rate in a microchannel heat sink as compared to using single-phase water cooling. The experiment was conducted with two-phase air–water flow in a single rectangular microchannel with a hydraulic diameter of 267 μm. The test section was made from copper. For a clear understanding, two-phase flow pattern, pressure drop, and heat transfer characteristics in the low Reynolds number of air–water flow were identified. The results show that segmented, throat-annular, throat-annular/liquid, and annular flow were observed within the test section. A flow pattern map was created and compared with the previous maps. The pressure drop can be predicted by the homogeneous flow model and the Friedel correlation separated flow model. The Nusselt number of segmented flow increases up to 1.2 times over the single-phase flow.
The correct prediction of gas-liquid two phase pressure drop is of immense significance for proper sizing of industrial equipment and safety operations involved in chemical, energy and petrochemical applications. The hydrostatic component of the two phase pressure drop is predicted based on the accurate estimation of void fraction. However, there exists a complexity in correct estimation of the frictional component of two phase pressure drop owing to interfacial friction at dynamic gas-liquid interface. The present study is focused on the experimental measurements of gas-liquid two phase frictional pressure drop and the performance evaluation of eleven correlations for its prediction in vertical downward orientation. The experimental determination of two phase frictional pressure drop is carried out for a 0.01252 m I.D. pipe with surface roughness of 0.0000152 m using air-water as the fluid combination. Unlike most of the other studies centered towards annular flow, this experimental study is spanned over different flow patterns and the entire range of the void fraction. In addition to the experimental measurements, the scope of this study also includes the performance analysis of eleven frictional pressure drop correlations available in the literature. These correlations are those based on the separated flow model initially proposed by Lockhart and Martinelli [1].The available frictional pressure drop correlations are compared against the data measured in the present study. Based on the experimental data available in the literature, the influence of the pipe diameter and fluid viscosity on the frictional pressure drop is also analyzed.
Flow regime, void fraction, rise velocity of slug bubbles and frictional pressure loss were measured for air-water flows in capillary tubes with inner diameters in the range from 1 to 4 mm. Although some flow regimes peculiar to capillary tubes were observed in addition to commonly observed ones, overall trends of the boundaries between flow regimes were predicted well by Mishima-Ishii’s model. The void fraction was correlated well by the drift flux model with a new equation for the distribution parameter as a function of inner diameter. The rise velocity of the slug bubbles was also correlated well by the drift flux equation. The frictional pressure loss was reproduced well by Chisholm’s equation with a new equation for Chisholm’s parameter C as a function of inner diameter.
In this study, a note on the mixture viscosity using the Shannak definition is presented [Shannak, B. A., 2008. Frictional pressure drop of gas liquid two-phase flow in pipes. Nucl. Eng. Des. 238, 3277–3284]. From his definition of the two-phase Reynolds number (Re(2ph)), an expression of the two-phase viscosity (μ(2ph)) is obtained. This expression of the two-phase viscosity (μ(2ph)) satisfies the following important limiting conditions: i. at x = 0, μ(2ph) = μf, and at x = 1, μ(2ph) = μg. This definition of the two-phase viscosity (μ(2ph)) can be used to compute the two-phase frictional pressure gradient using the homogeneous modeling approach in circular pipes, minichannels and microchannels. By plotting μ(2ph)/μf versus x for air–water system at atmospheric conditions using the Shannak definition as well as the other most commonly used formulas of the two-phase viscosity (μ(2ph)) in gas–liquid two-phase flows such as McAdams et al. (1942), Cicchitti et al. (1960), and Awad and Muzychka (2008) (Definition 1, Definition 2, Definition 3, and Definition 4), it is clear that the Shannak definition of the two-phase viscosity gives μ(2ph) > μf at low x. This is impossible because we must have μg < μ(2ph) < μf for 0 < x < 1. Therefore, attention must be taken when using the Shannak definition of the two-phase viscosity at low x.
The main objective of this study is to present new equations for a flow pattern independent drift flux model based void fraction correlation applicable to gas–liquid two phase flow covering a wide range of fluid combinations and pipe diameters. Two separate sets of equations are proposed for drift flux model parameters namely, the distribution parameter (Co)(Co) and the drift velocity (Ugm)(Ugm). These equations for CoCo and UgmUgm are defined as a function of several two phase flow variables and are shown to be in agreement with the two phase flow physics. The underlying data base used for the performance verification of the proposed correlation consists of experimentally measured 8255 data points collected from more than 60 sources that consists of air–water, argon–water, natural gas–water, air–kerosene, air–glycerin, argon–acetone, argon–ethanol, argon–alcohol, refrigerants (R11, R12, R22, R134a, R114, R410A, R290 and R1234yf), steam–water and air–oil fluid combinations. It is shown that the proposed correlation successfully predicts the void fraction with desired accuracy for hydraulic pipe diameters in a range of 0.5–305 mm (circular, annular and rectangular pipe geometries), pipe orientations in a range of -90°⩽θ⩽90°-90°⩽θ⩽90°, liquid viscosity in a range of 0.0001–0.6 Pa-s, system pressure in a range of 0.1–18.1 MPa and two phase Reynolds number in a range of 10 to 5 × 106. Moreover, the accuracy of the proposed correlation is also compared with some of the existing top performing correlations based on drift flux and separated flow models. Based on this comparison, it is found that the proposed correlation consistently gives better performance over the entire range of the void fraction (0 < α < 1) and is recommended to predict void fraction without any reference to flow regime maps.
Using an analogy between thermal conductivity of porous media and viscosity in two-phase flow, new definitions for two-phase viscosity are proposed. These new definitions satisfy the following two conditions: namely (i) the two-phase viscosity is equal to the liquid viscosity at the mass quality = 0% and (ii) the two-phase viscosity is equal to the gas viscosity at the mass quality = 100%. These new definitions can be used to compute the two-phase frictional pressure gradient using the homogeneous modeling approach. These new models are assessed using published experimental data of two-phase frictional pressure gradient in circular pipes, minichannels and microchannels in the form of Fanning friction factor (f{sub m}) versus Reynolds number (Re{sub m}). The published data include different working fluids such as R-12, R-22, argon (R740), R717, R134a, R410A and propane (R290) at different diameters and different saturation temperatures. Models are assessed on the basis minimizing the root mean square error (e{sub RMS}). It is shown that these new definitions of two-phase viscosity can be used to analyze the experimental data of two-phase frictional pressure gradient in circular pipes, minichannels and microchannels using simple friction models. (author)
Experiments of air water two-phase flow frictional pressure drop of vertical and horizontal smooth and relatively rough pipes were conducted, respectively. The result demonstrated that the frictional pressure drop increases with increasing relative roughness of the pipe. However, the influence of the relative roughness becomes more evident at higher vapour quality and higher mass flux. A new prediction model for frictional pressure drop of two-phase flow in pipes is proposed. The model includes a new definition of the Reynolds number and the friction factor of two-phase flow. The proposed model fits the presented experimental data very well, for vertical, horizontal, smooth and rough pipes. Therefore, the reproductive accuracy of the model is tested on the experimental data existing in the open literature and compared with the most common models. The statistical comparison, based on the Friedel’s Data-Bank containing of about 16,000 measured data, demonstrated that the proposed model is the best overall agreement with the data. The model was tested for a wide range of flow types, fluid systems, physical properties and geometrical parameters, typically encountered in industrial piping systems. Hence, calculating based on the new approach is sufficiently accurate for engineering purposes.
A particular phenomenon of turbulence reduction in bubbly two-phase flow is discussed based on the experimental observations and theoretical derivation of turbulence energy balance equations. The importance of the mechanisms involved in this phenomenon has been stressed for a better understanding of the complex nature of bubbly two-phase flow. It has been concluded that the local turbulence energy of the liquid phase can be changeable to an energy required to maintain the surface structure and vice versa, which in turn relates to turbulence energy dissipation through the fragmentation process of turbulence eddies. It is also suggested that the phase distribution mechanism is interrelated to the above mentioned energy exchange mechanism.
Experimental work on two-phase vertical upward flow was carried out using a 19mm internal diameter, 7m long pipe and studying the time series of cross-sectional average void fractions and pressure gradient which were obtained simultaneously. With the aid of a bank of published data in which the pipe diameter is the range from 0.5 to 70mm, the effect of pipe diameter on flow characteristics of two-phase flow is investigated from various aspects. Particularly, the work focuses on the periodic structures of two-phase flow. Average film thicknesses and the gas flow rate where slug/churn and churn/annular flow transitions occur all increase as the diameter of the pipe becomes larger. On the other hand, the pressure gradients, the frequencies of the periodic structures and the velocities of disturbance waves decrease. The velocity of disturbance waves has been used to test the model of Pearce (1979). It is found that the suggested value of Pearce coefficient 0.8 is reasonable for lower liquid flow rates but becomes insufficient for higher liquid flow rates.
Despite the importance of pressure drop in two-phase flow processes, and the consequent extensive research into the topic, there is still no satisfactory method for calculating two-phase pressure drop. In this article a theoretically based flow pattern dependent calculation method is adapted to yield a simple predictive method in which flow pattern influences are partially allowed for in an implicit manner and therefore need not be taken into account when using the method. (A)
Core annular flow pattern, where a low viscosity liquid surrounds a very-viscous one, may be very interesting for heavy oil transportation. However, in oil production, oil and water rarely flow alone and gas is usually present. Despite several publications on liquid–liquid core annular flow, no much work has been done towards a proper characterization of the effect of gas on pressure drop. The aim of this paper is twofold: to provide a new data base on three-phase (very-viscous-oil/water/air) flow, and to propose a simple model for the determination of pressure drop.
A new correlation for the prediction of frictional pressure drop for two-phase flow in pipes is suggested which is simple and more convenient to use than other methods. To determine their reliabilities, this correlation and fourteen correlations from the literature were checked against a data bank containing 9300 measurements of frictional pressure drop for a variety of fluids and flow conditions. It was found that the best agreement between predicted and measured values was obtained using the correlation suggested by Bandel. Somewhat less but still reasonable accuracy of pressure drop prediction is provided by a group of identified correlations, which includes the correlation described in this paper.ZusammenfassungEs wird eine neue Gleichung zur Berechnung des Reibungsdruckverlustes bei der Gas—Flüssigkeitsströmung in Rohren vorgestellt. Diese Korrelation ist wesentlich einfacher als bisher publizierte Rechenverfahren und enthält nur zwei Anpassungsparameter, von denen der eine den Wert 2 und der andere den Wert 3 hat. Mit der neuen Korrelation und mit 14 Korrelationen anderer Autoren berechnete Werte wurden mit etwa 9300 Messwerten des Reibungsdruckverlustes verschiedener Gas—Flüssigkeitsströmungen verglichen. Dabei wurde festgestellt, dass die von Bandel vorgeschlagene Korrelation die beste Übereinstimmung zwischen berechneten und gemessenen Werten ergibt. Es folgt eine Gruppe von Korrelationen, zu der auch die in dieser Arbeit vorgeschlagene Korrelation gehört, die eine immer noch brauchbare Voraussage des Reibungsdruckverlustes ermöglichen. Abweichungen zwischen berechneten und gemessenen Reibungsdruckverlusten von durchschnittlich über 30% müssen beim heutigen Stand des Wissens immer noch akzeptiert werden.
A general expression which can be used either for predicting the average volumetric concentration or for analyzing and interpreting experimental data is derived. The analysis takes into account both the effect of nonuniform flow and concentration profiles as well as the effect of the local relative velocity between the phases. The first effect is taken into account by a distribution parameter, whereas the latter is accounted for by the weighted average drift velocity. Both effects are analyzed and evaluated. The results predicted by the analysis are compared with experimental data obtained for various two-phase flow regimes, with various liquid-gas mixtures in adiabatic, vertical flow over a wide pressure range. Good agreement with experimental data is shown.
LCONTENTS; PART ONE; BASIC FLUID FLOW; FLUIDS IN MOTION; FLOW OF INCOMPRESSIBLE NEWTONIAN FLUIDS IN PIPES AND CHANNELS; FLOW OF INCOMPRESSIBLE NON-NEWTONIAN FLUIDS IN PIPES; PUMPING OF LIQUIDS; MIXING OF LIQUIDS IN TANKS; FLOW OF COMPRESSIBLE FLUIDS IN CONDUITS; FLOW OF TWO PHASE GAS LIQUID MIXTURES IN PIPES; FLOW MEASUREMENT; FLUID MOTION IN THE PRESENCE OF SOLID PARTICLES; INTRODUCTION TO UNSTEADY STATE FLUID FLOW: PART TWO: VECTOR METHODS IN FLUID FLOW; VECTOR METHODS IN FLUID FLOW AND THE EQUATIONS OF CONTINUITY AND MOMENTUM TRANSFER; APPLICATIONS OF MODIFIED NAVIER STOKES EQUATIONS IN RECTANGULAR COORDINATES; APPLICATIONS OF MODIFIED NAVIER STOKES EQUATIONS IN HORIZONTAL CYLINDRICAL COORDINATES; APPLICATIONS OF MODIFIED NAVIER STOKES EQUATIONS IN VERTICAL CYLINDRICAL COORDINATES.
Incluye índice Flujo de fluidos para ingenieros químicos.
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