Can Kang

Jiangsu University · School of Energy and Power Engineering

This study presents a comprehensive analytical approach to address the complexities of flow and heat transfer in planar Taylor–Couette systems. Utilizing innovative simplifying assumptions and conversion variables, we analyze the fluid dynamics between two cylinders, where the outer cylinder is hotter, and the inner cylinder rotates at a higher vel...

A centrifugal pump incorporating two inlets and a double-layered impeller is proposed for transporting a mixture of sand and water. The double-layered impeller (primary impeller) encircles a secondary impeller. To reveal the operating and flow characteristics of such a pump, numerical work is conducted with a validated numerical method. The effects...

The present study aims to elucidate the relationship between bubble behaviors in the spray sheet and internal bubbly flow of the air-induction nozzle. An experimental work was performed using the visualization technique. Effects of the air inlet position and spray pressure were investigated. The results show that compared with the bubbles inside th...

Phase change materials (PCMs) are frequently utilized in the thermal sector, especially for thermal energy storage (TES) applications. The purpose of this study was to analyze the thermal efficiency and melting characteristics of a leaf-vein-shaped fin in a triplex tube heat exchanger. The analysis focused on the use of pure molten salt PCM and a c...

In the present study, we investigate the water entry of three hollow cylinders with fronts of different fillet radii of 0, 5, and 10 mm. Particular attention is given to the effect of fillet radius of front on cavity dynamics. To interpret the mechanism of cavity evolution, a high-speed photography system is employed to capture instantaneous impact...

Following the impact of a superhydrophobic sphere on water, the formation of a stable-streamlined gas cavity undergoes several stages characterized by impact load slamming, cavity flow forming, cavity collapse, and unstable cavity. The former three stages have been extensively investigated. However, limited attention has been given to the post-coll...

The deposition of spray droplets is a hot topic in the field of plant protection. The air-induction nozzle, which is commonly used in agricultural spray, can produce droplets containing bubbles. However, few studies have addressed the deposition of hollow droplets. In the present study, we used experimental and numerical methods to investigate the...

The erosive wear encountered in some industrial processes results in economic loss and even disastrous consequences. Hitherto, the mechanism of the erosive wear is not clear, especially when the erosive wear is caused by large particles (>3.0 mm) carried by a flowing liquid. Current approaches of predicting erosive wear need improvement, and the op...

Electric water pumps (EWPs) are characterized by small sizes and variable operating conditions. Efficient operation of such a pump is important for the whole thermal management system. Here, comprehensive hydraulic optimization was performed to improve the performance of an EWP. The computational fluid dynamics technique was used to assist in the o...

In the present study, the collision between a falling droplet and a rising Worthington jet was experimentally studied. The event is followed by the monodispersedly dripping of coaxial binary droplets into a quiescent pool of glycerol solution. Different concentrations of the solution are considered. Unique droplet–jet collision characteristics are...

Phase change materials (PCMs) are now being extensively used in thermal energy storage (TES) applications. Numerous researchers conducted experiments using various circumstances and materials to optimize storage performance. A study was conducted to compare the numerical research of the melting process of paraffin wax using a hybrid nano-integrated...

The presented study aims to reveal flow and heat transfer characteristics as a translating aluminum plate is impinged by high-temperature gas discharged from inclined slot nozzles. The computational fluid dynamics (CFD) and the fluid-solid interaction (FSI) techniques were used to simulate the impingement process. A comprehensive comparison of flow...

The present study aims to plumb blockage of the deep-sea mining pump transporting large particles with different shapes. A numerical work was performed through combining the computational fluid dynamics (CFD) technique and the discrete element method (DEM). Six particle shapes with sphericity ranging from 0.67 to 1.0 were selected. A velocity trian...

Oil-based emulsion is a common herbicide formulation in agricultural spray, and its atomization mechanism is different from that of water spray. In this paper, a theoretical model based on the characteristics of spray sheets was proposed to predict the spray droplet size for oil-based emulsion spray. An image processing method was used to measure d...

This study aims to reveal the effect of the blade chord length on the startup performance of the lift rotor that converts the kinetic energy of tidal currents. The computational fluid dynamics technique was used to simulate unsteady flows around the rotor. The six degrees of freedom method was adopted to model the correlation between the rotational...

The present study aims to explain the effect of impeller structure on performance of a double-volute centrifugal pump. The impeller with 5 long blades and 10 splitter blades was proposed. An experimental work was performed to compare performance between the pumps equipped separately with the proposed and the conventional impellers. Distribution of...

The bubbly flow is encountered in many industrial processes. Numerical efforts dedicated to the explanation of the bubbly flow physics have never been overemphasized. Based on the computational fluid dynamics (CFD) technique, the volume of fluid (VOF) method has been adopted to predict flow phenomena in nuclear reactors. For the VOF method, a volum...

The present study aims to reveal the operational characteristics of the needle-free injector. Effects of operating parameters on the injection performance were experimentally investigated. A visualization experiment was performed to describe the dispersion pattern of water in gel. The results show that the peak stagnation pressure increases continu...

BACKGROUND The air‐induction spray featured by air bubbles involved in the spray sheet has attracted great attention in applications of agricultural spray due to its advantages of alleviating spray drift and promoting deposition. The objective of the presented study is to deepen the understanding of the mechanism of the air‐induction spray through...

The needle-free injection is a new technique for treating subcutaneous drug delivery through penetrating the skin with a high-speed liquid drug jet. The present study aims to reveal fluid dynamics characteristics of the needle-free injection. The operational parameters such as the driving pressure, the nozzle diameter and the liquid volume were inv...

The present study aims to describe the characteristics of the hydraulic transport of manganese nodules in a vertical pipe. The solid–liquid two-phase flows were simulated using a numerical technique that combines the computational fluid dynamics (CFD) method and the discrete element method (DEM). Manganese nodules with diameters of 5.0 mm, 15.0 mm,...

BACKGROUND The air‐induction nozzle greatly reduces drift potential by increasing spray droplet size compared with a standard flat‐fan nozzle. The current study aims to reveal the mechanism behind the formation of large droplets through the air‐induction nozzle from the aspect of bubble evolution in the spray sheet. RESULTS Bubble break‐up leads d...

Effects of the incident shear flow on operational performance of a drag-type hydrokinetic rotor were investigated numerically. A flow visualization experiment was conducted to validate the numerical method. Energy conversion ability of the rotor under different incident shear flow conditions were analysed. The effects of the tip speed ratio were al...

The present study aims to reveal two-phase flow characteristics as gas is injected into co-flowing water. A computational fluid dynamics work was conducted using the volume of fluid model and the delayed detached eddy simulation. The numerical scheme was validated through experimental results. Effects of the upstream water velocity and the gas inje...

The present study aims to reveal behaviors of leaded brass as it is exposed to the synergetic effect of corrosion and cavitation erosion. The specimens were submerged in seawater for ultrasonic cavitation erosion experiments. The cumulative mass loss, surface microstructure and three-dimensional surface morphology were analyzed to characterize the...

Among the techniques of subcutaneous drug delivery, the needle-free injection is relatively new. Compared to the hypodermic syringe, the needle-free injection avoids accidental stabbing and cross-infection. Although the needle-free injection technique has been exercised, the knowledge about instantaneous behaviors of the drug during the injection p...

The present study aims to reveal startup characteristics of a two-stage drag-type hydrokinetic rotor. Numerical simulation was performed to capture instantaneous flow characteristics and to develop a relationship between flow and rotor performance. The dependence of the rotational speed on hydraulic loads was modeled and solved using the six degree...

An experimental work was conducted to investigate effects of the deflector plate on the performance and flow characteristics of a drag-type hydrokinetic rotor. A measurement device was specifically designed to record instantaneous rotational speed and output torque of the hydrokinetic rotor. The performance of the rotor and the near-rotor flow were...

Gas-liquid flow has a strong relationship with energy transfer, production, and transportation. A black-box method based on velocity information and deep learning was proposed to identify the sub-regimes of gas-liquid flow in real time, including two parts—data acquisition and establishment of the identification model. The Ultrasound Doppler Veloci...

The present study aims to describe the interaction between rising bubbles of different sizes. Coaxial and triangle bubble configurations were investigated. Bubble sizes ranged from 4.0 mm to 10.0 mm. Three-dimensional unsteady numerical simulations were performed and the volume of fluid multiphase model was employed. The numerical scheme was valida...

Oil-based emulsions are been widely used to apply agricultural sprays and they are often delivered through flat-fan spray nozzles mounted on booms. Perforations are one of the typical structures of found during the atomisation of oil-based emulsions, and they are investigated here using visualisation. The generation, development and coalescence of...

The liquid lead-bismuth pump is a core component of the main coolant circuit of the accelerator driven system. The pump performance has a significant effect on the safety and operational stability of the whole system. A liquid lead-bismuth pump was designed and the performance and flow characteristics of the pump were obtained numerically. Effects...

The present study aims to describe effects of an upstream deflector on flow characteristics and startup performance of a drag-type hydrokinetic rotor. Flow velocity was measured using the time-resolved particle image velocimetry (TR-PIV). The operation performance of the drag-type rotor was measured. The rotational speed of the rotor was calculated...

The present study aims to reveal gas-liquid flow patterns as gas is injected into co-flowing water. An experimental work was conducted in a loop in which pure water was circulated. The gas-injection nozzle was submerged in the flowing water. Effects of the water flow velocity and gas flow rate were jointly considered. Two-phase flow patterns were v...

The hydrokinetic rotor serves as a critical component in the system of hydropower utilization. Advantages of the drag-type rotor have been recognized while the disadvantages of low efficiency are appreciable. To improve the performance of the drag-type rotor, studies have been performed from multiple aspects. The present study summarized recent ach...

The present study aims to reveal startup characteristics of a drag-type rotor as it is used to harness kinetic energy of flowing water. The rotational speed of the rotor and the hydraulic loads exerted on the rotor were correlated. After being validated through experimental results, a numerical scheme was used to investigate instantaneous flow para...

A twin-fluid nozzle was proposed for low-pressure atomization. The nozzle is featured by swirling air flows in the mixing chamber. Liquid medium is thereby inhaled due to the pressure difference. An experimental work was performed to investigate the atomization performance of the nozzle and the hydrogen peroxide solution served as the liquid medium...

Oil-based emulsions are commonly formulations in agricultural spraying but their spray break-up behaviour and droplet characteristics differ from those when water is sprayed. In this paper, the effect of spray structure on the droplet characteristics, droplet size distribution and droplet velocity, were investigated using the high-speed photomicrog...

Two-phase flow regime identification in a horizontal pipe was realized based on the liquid phase velocity information and the machine learning method. Ultrasound Doppler velocimetry was employed to measure the liquid velocity. Statistical features extracted from the velocity time series data, such as mean, root mean square, and power spectral densi...

The ASTM G134 standard, Standard Test Method for Erosion of Solid Materials by Cavitating Liquid Jet, provides specifications for assessing the material resistance to the cavitation erosion caused by submerged cavitating jet. Nevertheless, the influence of test chamber dimensions on cavitation erosion is not considered in such an international stan...

The present study aims to evaluate the operational stability of an impeller pump transporting high-temperature molten salt. A numerical strategy incorporating the computational fluid dynamics (CFD) technique and finite element analysis was designed. The coupling between fluid flow, temperature and structure was enabled. Effects of the flow rate of...

The aim of the present study is to reveal characteristics of a rising bubble in quiescent mineral oil. Three air‐injection nozzles with outlet diameters of 1.0, 2.0, and 3.0 mm were selected. Consecutively rising bubbles were produced as air was injected into mineral oil. Bubble visualization was implemented using the high‐speed photography techniq...

The present study aims to reveal characteristics of a bubble as it passes through the interface between two immiscible liquids, namely deionized water and mineral oil. Air was injected into the deionized water to produce bubbles. Initial bubble sizes were varied through using three nozzles with the outlet diameters of 2.0, 3.0 and 4.0 mm respective...

To investigate the response of material to cavitation erosion, a comparative work was carried out on three materials, aluminum, copper alloy and titanium. Ultrasonic cavitation erosion was produced as the specimen was submerged in the deionized water. Within a cavitation erosion period of 120 min, the cumulative mass loss was measured at certain ti...

The present study aims to reveal solid-liquid two-phase flow patterns in a pumping station which is featured by the deployment of two pumps in a cylindrical tank. The computational fluid dynamics technique (CFD) was used to simulate the flows. The numerical scheme constructed was validated through solid particle velocity measured using a phase Dopp...

The aim of the present study is to reveal fundamental cavitation erosion characteristics of the curved surface. The submerged waterjet was used to produce cavitation. An experimental work was performed on a standard cavitation erosion test rig. The Al 5083 specimens with three curvature radii, 7.0, 9.0 and 10.0 mm, were selected as the target speci...

For an in-line arrangement of two drag-type hydrokinetic rotors, flow patterns between the two rotors and the rotor performance were investigated. The flows were measured using time-resolved particle image velocimetry (TR-PIV) technique. Computational fluid dynamics (CFD) technique was used to quantify the rotor performance. Emphasis was placed upo...

A combinative use of the photovoltaic modules and roof coating on building was implemented for an institutional hall in Ghana. Computational fluid dynamics simulation was performed for both coated and uncoated roofs to investigate the heat transfer on the roof with regards to the temperature reduction. Numerical results were compared with the field...

Driven by high pressures, the submerged waterjet is featured by high velocity and cavitation, which arouse unsteady flow signals. To elucidate the temporal and spatial characteristics of the high-pressure submerged waterjet, an experimental work was carried out with the waterjet submerged in a square duct and jet pressures varied from 50 to 320 MPa...

To investigate the characteristics of the bubbles trapped in liquid cross flow, air was injected into flowing water circulated in a closed loop. High speed photography was used to record bubble images instantaneously. An image-processing code was specifically developed to identify bubbles in the images and to calculate bubble parameters. Effects of...

A modified Savonius hydrokinetic rotor was proposed. Flows near the rotor were measured using the time-resolved particle image velocimetry (TR-PIV)technique. Effects of the rotor angle and upstream velocity were described. The rotor geometry was further optimized and the rotor performance was evaluated using the computational fluid dynamics (CFD)te...

The Savonius hydraulic turbine is effective in harnessing the energy carried by flowing water. The advantages of the Savonius hydraulic turbine, such as simple in structure and good start-up characteristics, have been acknowledged. Nevertheless, the lack of a detailed investigation of the flows around the Savonius hydraulic rotor hampers the techni...

To investigate cavitation phenomenon in acetic acid solution, numerical simulation was performed using the commercial computational fluid dynamics code of ANSYS Fluent. A comparison for acetic acid solutions of different concentrations flowing in a Venturi tube was implemented, focusing on the effect of the solution concentration on cavitation. Dis...

The aim of the presented study is to reveal patterns of the bubbles traveling in liquid flow. Air was injected into flowing water via a cylindrical nozzle that protrudes in the flow. Bubble images were recorded using high-speed photography. Water flows under no-bubble condition were measured using particle image velocimetry (PIV). Effects of the me...

High flexibility of prefabricated pumping stations in collecting and transporting storm water has been recognized. Nevertheless, flows inside such a complex system have rarely been reported. The present study aims to reveal water-sand flow characteristics in a prefabricated pumping station and to optimize geometric parameters of the tank to mitigat...

To investigate the ultrasonic cavitation erosion in NaHCO 3 solutions, experiments with copper alloy specimens were carried out. Three NaHCO 3 solutions with concentrations of 0.3%, 3% and 6% were used as liquid mediums in which the vibration horn and the target specimen were mounted. A systematic evaluation and comparison of cavitation erosion eff...

The bubbly flow is an important flow pattern in fluids engineering. A variety of bubbly flows have been witnessed so far; bubble size and bubble volume fraction are two factors that affect the appearance of the bubbly flow. In consideration of the shortage of numerical simulation in the presence of bubbly flows, the supplement of the knowledge of b...

Theoretical, experimental and numerical methods are three primary methods that are commonly used in fluids engineering. For the theoretical method, it requires a sound base of mathematical and mechanical knowledge. Meanwhile, the gap between theoretical results and applications is often remarkable. In contrast, the latter two methods can be easily...

Injecting air into water serves as an effective measure of generating bubbles. The characteristics of the background water flow must exert a significant effect on the bubbles trapped. In this chapter, it is intended to reveal the bubbly flow pattern downstream of a cylinder. Therefore, a cylinder is installed in the horizontal transparent section o...

The advantages of the drag-type rotor in wind energy utilization have been widely acknowledged. In recent years, the exploitation of water energy in off-shore regions, rivers or even pipes guides the application of the drag-type rotor into a new stage. In this chapter, a drag-type rotor operating in the medium of water is investigated. The water tu...

This book describes recently developed research methods used to study complex problems in fluid engineering, especially optical flow measurement, flow visualization and numerical methods. It includes a wealth of diagrams and images, and the content is presented in a step-by-step manner from beginning to end, helping readers grasp the central points...

Emphasis of this chapter is placed on the cavitation phenomenon arising in a condensate pump. The condensate pump is unique since the amount of gas in the inflow cannot be neglected. It is the responsibility of optimal design to relieve the cavitation effect. Research tools are to be used to validate the innovation. For the pump considered, the imp...

For fluid machinery, the interaction of fluid and solid components cannot be neglected. Sometimes, engineers care more about the solid parts than flows. Therefore, the effects of fluid on the solid parts have attracted efforts from multiple aspects. It should be noted that the shortages of current experimental techniques in treating these issues ar...

Fluids engineering is a huge subject and involves not just fluid machinery but also the entire flow system. The major foundations of fluids engineering are fluid mechanics and mechanical principles. A tendency in recent years is new flow phenomena are constantly revealed. Meanwhile, the complexity of these flow phenomena is apparently high. A broad...

Flows in the impeller pump are typical among engineering fluid flows. In this chapter, we select a low-specific-speed centrifugal pump as an example to demonstrate research methods commonly used in this aspect. This pump is equipped with long and short blades. Both the pump performance and inner flow characteristics at various flow rates are studie...

Successful applications of waterjet have been observed in engineering fields. For submerged waterjet, the interaction between the jet stream and ambient water is intricate. As the jet pressure is high, cavitation might occur; meanwhile, due to the resistance of surrounding water, the integrity of the jet stream will be ruined rapidly after the wate...

To seek and describe the influence of bubble size on geometric and motion characteristics of the bubble, six nozzles with different outlet diameters were selected to inject air into water and to produce different bubble sizes. High-speed photography in conjunction with an in-house bubble image processing code was used. During the evolution of the b...

To1 investigate the behavior of the axial-flow pump blade as it is exposed to the impact of solid particles, numerical simulation was performed. The commercial code of ANSYS was used to obtain the distribution of the equivalent stress over blade surface. The rotational speed of the impeller and particle size were considered. A comparative analysis...

The emphasis of the present study was placed on the impeller of a centrifugal feed pump. A comparative investigation was implemented between three impeller schemes, one with ten equal-length blades and the other with five long and five short blades. Numerical simulation was performed to investigate the flow field associated with the three schemes....

To investigate the characteristics of the bubble which is exposed to the liquid cross flow, the method of ventilation was adopted and air was injected into the water flow. A water tunnel was used to provide uniform water flow with variable velocity magnitude. A high speed camera was used to record instantaneous bubble images. An image-processing co...

A prefabricated pumping station catering to the delivery of medium with high flow rate is investigated. Two configurations of storage tanks are devised. Computational fluid dynamics (CFD) is utilized to acquire flow patterns in the pumping station as the pumps operate concurrently. Flow rate allocation and the disturbance of pump operation to ambie...