Wei Li

Jiangsu University · Research Center of Fluid Machinery Engineering and Technology

In recent years, it has been demonstrated for many two- and three-dimensional external and internal turbulent flows that the one-equation Wray-Agarwal turbulence model can compute the complex turbulent flow fields with high computational accuracy, excellent computational convergence and efficiency. In this paper, Wray-Agarwal (WA) turbulence model...

Rotating stall always occurs in the mixed-flow pump operating at partial load condition, not merely affecting the unit efficiency, but also generating more serious turbulent flow fields. The tip leakage vortex (TLV), as a classic vortex structure in hydraulic machinery, is deserved to investigate the impact on the energy conversion instability of m...

This research presents the new techniques and practical experiences of using unmanned aerial vehicles (UAVs) precision agriculture mapping. UAV-based remote sensing systems should be cost-effective, fast-producing, have high geometric accuracy, and be simple to operate by local staff. This work aims to: (1) precisely use high-resolution UAV thermal...

Rotating stall suppression is an important means to improve the high-efficiency range of hydraulic machinery operation, including active suppression and passive suppression, and finding a cost-effective, practical and reliable passive suppression scheme is an urgent need in the current fluid machinery market. At present, due to the effectiveness an...

The energy consumption of various pumps accounts for almost 20% of the world’s electricity production, and the improvement of pump efficiency could save enormous energy consumption globally. In a mixed-flow pump, the hydraulic loss within the shroud region accounts for almost 30% of the whole loss in the impeller, which is an inevitable factor. The...

Tip leakage flow (TLF) is not only an important factor causing hydraulic loss in mixed-flow pump, but also one of the inceptions of rotating stall. At present, limiting the stall of rotating machinery by restraining the TLF has gradually become a research hotspot of rotating machinery. However, in the field of mixed-flow pump, it is still in the in...

Centrifugal pumps are frequently utilized in general machinery, but they have issues with low efficiency, unstable operation, and high-power consumption in actual engineering, making performance improvements necessary. In this paper, the particle swarm algorithm is utilized to find the optimal solution among the Pareto front solutions and obtain th...

To study the influence of an elbow inlet on the rotating stall characteristics of a waterjet propulsion pump (WJPP), a three-dimensional internal flow field in a WJPP under a straight-pipe inlet and elbow inlet is numerically simulated. By comparing the hydraulic performance of WJPP under the two inlet conditions, the internal relationship between...

The aerial platforms have the potential of realizing the precision agriculture, especially the rational allocation of water resources and the intelligent irrigation management of crops. This paper investigates a Unmanned Aerial Vehicle (UAV)-assisted intelligent monitoring method of soil temperature and moisture. The UAV platform is equipped with a...

Remotely-sensed data are a source of rich information and are valuable for precision agricultural tasks such as soil quality, plant disease analysis, crop stress assessment, and allowing for better management. It is necessary to validate the accuracy of land surface temperature (LST) that is acquired from an unmanned aerial vehicle (UAV) and satel...

This paper presents the matching characteristics of impellers and guide vanes of high capacity and pressure seawater desalination pumps by using computational fluid dynamics (CFD). The single-stage pump is numerically calculated, and its external characteristics are consistent with the test results of model pump. Taking this scheme as a prototype,...

Water management is becoming a critical issue for sustainable agriculture, especially in the semi-arid region, where problems with water scarcity are rising. More accurate water status recovery in crops is required for precise irrigation through remote sensing technologies. These technologies have a lot of potential in intelligent irrigation becaus...

Based on CFD analysis technology, this paper studies the cavitation performance of an LNG submerged pump and the pressure pulsation characteristics under cavitation excitation. The variation laws of the waveform, amplitude and frequency of the pressure pulsation in the impeller of the LNG submerged pump under different flow rates and NPSHa are also...

A submerged high-pressure water jet is usually accompanied by severe cavitation phenomenon. An organ pipe nozzle can greatly improve the cavitation performance of the jet, making use of the self-excited oscillation of the flow. In order to study the effect of organ pipe nozzles of different nozzle outlet shapes on cavitation behavior of submerged h...

A multi-region dynamic slip method was established to study the internal flow characteristics of the mixed-flow pump under the Alford effect. The ANSYS Fluent software and the standard k-ε two-equation model were used to numerically predict the mixed-flow pump’s external characteristics and analyze the forces on the impeller and guide vane internal...

In order to study the effect of different numbers of impeller blades on the performance of mixed-flow pump “saddle zone”, the external characteristic test and numerical simulation of mixed-flow pumps with three different impeller blade numbers were carried out. Based on high-precision numerical prediction, the internal flow field and tip leakage fl...

Co-gasification is considered as a useful technique for post-treatment of anaerobic digestion residues. The present study has dealt with the efficiency parameter of 24 kWe downdraft biomass gasifier with 50% mixture ratio of wood chips + corn cobs and 50% ratio of sugarcane bagasse + coconut shells. The performance of the gasification process was a...

The submerged high-pressure water jet has the characteristics of high velocity, strong turbulence, and severe cavitation. In order to reveal the formation mechanism of shear cavitation in the submerged high-pressure water jet and to grasp the turbulent structure and velocity distribution characteristics in the jet, the prediction ability of differe...

With the development of green manufacturing technology, high-pressure cavitation water jet cleaning and shot peening technologies are gradually replacing traditional high-pollution processes. To improve the processing quality and efficiency, three types of metal alloys are impinged with cavitation jet under different processing parameters. By chang...

In a mixed-flow pump, the energy performance curve always appears as an unsteady region under rotating stall condition. In this paper, computational fluid dynamics (CFD) technology is employed to study the effect of variation in blade thickness of the impeller for the purpose of improving the stall characteristics of the mixed-flow pump. The local...

This paper investigates the influence of different tip clearances on the transient characteristics of mixed-flow pump under stall condition. The instantaneous internal flow fields of mixed-flow pump with four tip clearances (0.2 mm, 0.5 mm, 0.8 mm and 1.1 mm) are explored by conducting unsteady time accurate simulations. Reynolds-averaged Navier-St...

Biomass gasification is a process of converting solid biomass ingredients into combustible gas, which can be used in electricity generation. A biomass gasifier was designed with 30–40 kg/h downdraft, fabricated, and evaluated using sugarcane bagasse and coconut shells. The effect of equivalence ratio on syngas composition, heating value, syngas yie...

The non-uniform disturbance in circumferential direction is main cause for occurrence of rotating stall in turbomachinery. In order to study the effect of tip clearance leakage flow on rotating stall, mixed-flow pump models with different tip clearances are simulated and energy performance curves and internal flow structures are obtained and compar...

The Wray–Agarwal (WA) turbulence model is selected to simulate the internal and external characteristics of a centrifugal pump with semispiral suction chamber; the numerical results are compared with the experimental data and computed results predicted by standard k–ε, renormalization group (RNG) k–ε, and shear stress transport (SST) k–ω turbulence...

This paper shows some practical experiences of using unmanned aerial vehicles-based platform for remote sensing in supporting precision agriculture mapping. There have been studies on unmanned aerial vehicles used to calculate plant water stress; however, the scientific reports of drone images that are used to predict best time and height are rare....

Water is a crucial element for plant growth, metabolic processes, and general health. Water-deficit, typically simplified by drought stress, is the most critical photosynthetic source of stress that restricts plant growth, crop yield, and food product quality. This research highlights state of the art, possibilities for detecting the canopy tempera...

This paper shows some practical experiences of using unmanned aerial vehicles-based platform for remote sensing in supporting precision agriculture mapping. There have been studies on unmanned aerial vehicles used to calculate plant water stress; however, the scientific reports of drone images that are used to predict best time and height are rare....

A stainless-steel cantilever multistage centrifugal pump was taken to study the transient response characteristic. The axial locus under different working conditions was tested experimentally and compared in detail. The results show that the gyroscopic effect increases the radial displacement located near the end element, and the amplitude of the r...

In order to further enrich the theory of rotational stall, this paper explored the mechanism of internal energy loss in the mixed-flow pump under stall condition based on the shear stress transport (SST) k-ω turbulence model, identified the vortices in the impeller by the Q-criterion method, and characterized the turbulence intensity by the turbule...

Three-dimensional (3D) unsteady Reynolds-averaged Navier–Stokes (URANS) simulations are conducted to investigate the blade load and internal flow field for a low specific centrifugal pump operating as a turbine (PAT). Validation and grid independence of the simulation method are performed and ensured. A thorough inspection to flow variables in term...

In order to investigate the influence of tip clearance size on the characteristics of mixed-flow pump under stall conditions, the entropy production analysis method is utilized to visualize the high energy loss area of main flow domains in internal flow fields. The results shown that the tip clearance size will not only affect the internal flow fie...

The motivation for this review paper came from the developing countries where the economy is mostly dependent on agriculture and climate conditions. Based on current conditions and historical records, profitability in production farming depends on making a right and timely operational decision. Precision farming is a systematic program designed to...

In order to study the internal flow fields of mixed-flow pump with eccentric impeller, the numerical simulation and experiment have been conducted based on the dynamic sliding multi-region method. During simulation, the impeller domain has been separated by three sub-domains to apply the whirl effect. The pressure, turbulent kinetic dissipation and...

In order to better understand the flow characteristics of mixed-flow pump with non-uniform tip clearance, a test rig is established and the flow fields of various cross section in impeller are studied based on particle image velocimetry technology. The velocity vector distributions of three cross sections, e.g., impeller blade inlet, middle and out...

Fluidized bed has gained popularity in the renewable energy industry due to its superior thermochemical conversion efficiency. Investigating the flow patterns inside the fluidized bed is of great importance to obtain detailed knowledge of the energy conversion of biofuel and to further optimize the combustion performance. In this paper, the effect...

In order to investigate the effect of various impeller tip clearances on the pressure pulsation in a mixed-flow pump, the energy performance test and pressure pulsation experiment of a mixed-flow pump with different tip clearances are studied simultaneously. The pressure pulsation signals at impeller inlet, middle, and oulet are processed and analy...

Agriculture is undoubtedly a leading field for livelihoods in China. As the population increases, it is necessary to increase agricultural productivity. By capturing the support and the increment in production on farms, the need for freshwater used for irrigation increases too. Presently, agriculture accounts for 80% of overall water uptake in Chin...

High-pressure submerged cavitation jet is widely used in the fields of material peening, petroleum drilling, and ocean engineering. The impact performance of the jet with intensive cavitation is related to the factors such as working condition and the nozzle geometry. To reveal the relationship between the nozzle divergent angle and the jet pressur...

To investigate the performance of engine cooling water pump in automobile with variable rotating speed, experimental tests and numerical simulation are carried out on an engine cooling water pump under the rotating speed of 2650, 2960, 3700, and 4300 r/min. The hydraulic performance under 3700 r/min rotating speed and the cavitation performance und...

The nuclear power valve is an important piece of equipment in any nuclear power system. The finite element method was used in this study to analyze the strength and rigidity of the high-temperature and high-pressure nuclear gate valve. The structural characteristics were optimized as per the parameters that affect the strength of the valve body. Fl...

In order to study the shaft system vibration of mixed-flow pump under rotor-stator interaction, the unsteady pressure fluctuation characteristics are measured and the rotor axis orbit obtained based on the Bentley 408 data acquisition system. The relationship between pressure fluctuation and vibration characteristics of shaft system at the blade pa...

In order to investigate the effect of impeller tip clearance on the internal flow fields and the hydraulic losses in mixed-flow pump, the entropy production method with computational fluid dynamics (CFD) is employed to analyze the energy losses in a low specified number mixed-flow pump with guide vane. The results show that the size of tip clearanc...

To analyze the internal flow of the engine cooling water pump (ECWP) under thermodynamic effect, Zwart cavitation model based on the Rayleigh-Plesset equation is corrected, and NACA0015 hydrofoil was selected to verify the corrected model. The cavitation performances of ECWP with different temperatures were numerically simulated based on a correcte...

In order to explore mechanism and propagation characteristics of rotating stall, the unsteady flow characteristics of a mixed-flow pump are calculated based on SST turbulence model. Based on pressure fluctuation characteristics, number of stall cells and circumferential propagation velocity are calculated accurately under different stall conditions...

The wind energy pump system is a new green energy technology. The wide high efficiency region of pump is of great significance for energy conservation of wind power pumping system. In this study, factorial experiment design (FED) and computational fluid dynamics (CFD) are employed to optimize the hydraulic design of wind energy centrifugal pump (WE...

In order to analyze the unsteady flow characteristic and the pressure fluctuation features of mixed-flow pump caused by the interaction between the impeller and guide vanes under part-load conditions, the unsteady flow field in the mixed-flow pump was numerically simulated based on the standard k–ε turbulence model. The pressure distribution and th...

The novel jet self-priming centrifugal pump, as important modern irrigation equipment, is widely used in large-scale irrigation, mine drainage and so on. In order to improve the profile streamline of blade, the inlet shape of impeller was designed as distorted and the outlet shape as cylindrical, which can not only improve the pump efficiency, but...

The self-priming pump as an essential energy conversion equipment is widely used in hydropower and thermal power plants. The energy losses in the internal flow passage of the pump directly affect its work efficiency. Therefore, it is important to improve the internal flow characteristic of the pump. In the present work, a novel self-priming pump wh...

In the current research, a high-pressure submerged cavitation jet is investigated numerically. A cavitation model is created considering the effect of shear stress on cavitation formation. As such, this model is developed to predict the cavitation jet, and then the numerical results are validated by high-speed photography experiment. The turbulence...

High speed rotating pump is the current trend in pump’s development and application, which has the advantages of compact size and energy-saving features. The electrical submersible pump, typically called an ESP, is an efficient and reliable artificial-lift method for lifting moderate to high volumes of fluids from wellbores, which have been wildly...

In order to investigate the effect of impeller tip clearance on internal flow fields and the rotating stall inception impacted by tip leakage vortex and inlet unsteady flow in a mixed-flow pump, mixed-flow pump models with tip clearances of 0.5 mm, 0.8 mm, and 1.1 mm were numerically calculated, and then the energy performance curves and internal f...

The transient characteristics of the inlet flow field of mixed-flow pump during start-up process are hard to be measured experimentally. The elbow structure with viewport is designed before the mixed-flow pump for capturing the transient inlet flow fields of the mixed-flow pump. Meanwhile, the synchronous data acceptance system is also designed to...

The non-uniform disturbance in the circumferential direction is the main cause for the occurrence of rotating stall in turbomachinery. In order to study the effect of tip clearance leakage flow on rotating stall, the mixed-flow pump models with different tip clearances are numerically simulated, and then the energy performance curves and internal f...

Hydraulic automatic gauge control (AGC) system is the core control system to ensure the thickness accuracy of cold-rolled plate, and the reliability of its load roll system is the key to guarantee the rolling process with high precision, high speed, continuity and stability. However, the working mechanism of hydraulic AGC system is complex. And it...

Due to the internal flow field is unstable under part-load condition, which has great influence on the structure strength of impeller. Therefore, in order to improve the operation stability, four different thickness distribution blades were proposed, the energy performance, internal flow field and structural dynamic characteristics under 0.2 Q were...

Mixed-flow pump is wildly used in industrial and agricultural fields, while the requirements for its stability become more and more restricted with the improvement of the capacities. When the pump is operated under part-loading conditions, unstable characteristic like rotating stall happens and brings intensive vibration and noise. To reveal the in...

As the conventional self-priming pump cannot satisfy the requirement of quick aerofluxus, a novel self-priming pump with distinct structure and the extraordinary self-priming mechanism was designed to afford promising opportunities for emergency water delivery. Meanwhile, to obtain the optimal profile of the blade, nine blades with different thickn...

Biomass gasification is a process of converting solid biomass ingredients into a combustible gas which can be used in electricity generation. Regardless of their applications in many fields, biomass gasification technology is still facing many cleaning issues of syngas. Tar production in biomass gasification process is one of the biggest challenges...

The conventional method cannot explicitly confirm the location and type of the energy loss, therefore this paper employs the entropy production theory to systematically analyze the category, magnitude and location of hydraulic loss under different blade thickness distribution. Based on the analysis, the turbulent entropy and viscosity entropy produ...

In order to reveal the relationship between rotor-stator interaction-induced unsteady flow and the shaft vibration of the mixed-flow pump, PIV (particle image velocimetry) and axis orbit experiments were carried out synchronously in a mixed-flow pump under designed flow rate (1.0 Qdes ) and the partial load conditions (0.4 Qdes and 0.2 Qdes ). The...

In order to study the influence rule of wrap angle of blade on the internal flow field and hydraulic performance of double suction pump, 5 kinds of wrap angles of blade with 100°, 110°, 120°, 130° and 140° are designed in this paper. The turbulence model and the grid type are analyzed, the performance of ES350-575 double suction pump is obtained by...

Two cavitation models with thermodynamic effects were established based on the Rayleigh-Plesset equation to predict accurately the cavitation characteristics in the high-temperature fluid. The evaporation and the condensation coefficient of the cavitation model were corrected. The cavitation flow of NACA0015 airfoil was calculated using the modifie...

In industrial processes such as chemical looping combustion, single-component spouted beds of monodisperse particles are very rarely used but the spouted beds of polydisperse particles have been widely used. The flow characteristics of polydisperse particles are much more complex than the single particle fraction in a fluidized bed. To investigate...

Purpose This paper aims to study the transient flow characteristics in a mixed-flow pump during the start-up period. Design/methodology/approach In this study, numerical calculation of the internal flow field in a mixed-flow pump using the sliding mesh method was carried out. The regulation of the pressure, streamline and the relative speed duri...

Space diffuser is one of the most critical flow components in electric submersible pumps; its hydraulic design has the significant effects on the pump performance. In this paper, a typical electric submersible pump was chosen as the research object to study the influence of space diffuser vanes number, by means of numerical simulation and experimen...

Purpose To study the transient hydraulic impact and overall performance during startup accelerating process of mixed-flow pump experimentally and numerically. Design/methodology/approach In this study, the impeller rotor vibration characteristics during starting period under the action of fluid-structure interaction was investigated, which is ba...

Purpose Pump is one of the most energy consuming devices widely used as general machinery in industrial applications. Computational Fluid Dynamics (CFD) have been became the main method to study the pump inner flow patterns. It is important to understand the differences and feat