bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on the transient cavitation characteristics in an axial flow tandem pump during the rapid starting period
Authors: Huang Jun , Zheng Fengchuan , Wang Yuhu , Chen Tairan , Wang Yana 
Published: October 2024

Abstract
In axial flow pump systems constrained by limited internal space, the advantages of axial flow tandem pumps are high space utilization, strong power capacity, and great thrust. The onset of cavitation during the rapid starting period poses a classic issue for tandem axial flow pumps, resulting in issues like noise, vibration, cavitation breakdown, and material damage. This article aims to investigate the transient cavitation characteristics of each flow passage component of an axial flow tandem pump during the rapid starting period by numerical simulation method. It is compared that the evolution laws of the cavity of each flow passage component. The evolution of the cavity in all flow passage components is strongly correlated with the flow rate change rate in each stage of the rapid starting period. Among all flow passage components, the first impeller firstly experiences cavitation, and its cavitation severity is also the most severe. The Effective Net Positive Suction Head (NPSHa
) can reduce the influence of transient effects on cavity prediction and better characterize the details of the cavity evolution in different impellers than the cavitation number σ during the rapid starting period. Meanwhile, The NPSHa
of the second impeller inlet is always higher than that of the first impeller inlet, indicating superior cavitation performance for the second impeller.
Study on the impact of turbulent spatiotemporal propagation in the outlet passage on the performance of vertical axial flow pumps.
Authors: Chen Bingning , Jin Yan , Song Xijie , Zhang Ye , Ni Debin 
Published: October 2024

Abstract
Pumping station engineering is crucial for our country’s national economy as a part of water conservancy infrastructure. The vertical axial flow pump commonly used in pumping station construction features a high flow rate and low discharge pressure. Understanding the impact of turbulence on the flow of water entering and leaving the pump unit is crucial for the efficient and reliable operation of a pumping station. This paper examines the internal flow and hydraulic characteristics of the device for vertical axial flow pump at a pumping station through numerical simulation technology and experimental validation. It is inferred that turbulent flow develops in the outlet flow passage while the pump device is currently functioning, impacting the impeller’s outlet bend and guide vane. This leads to the formation of vortices, backflow, and folding flow at the guide vane and outlet bend. As water flows out through the outlet passage, bias and backflow develop, causing erosion on both sides of the outlet pool and impacting the pump unit’s overall head and efficiency.
Influence of axial distance between impeller and diffuser on the hydraulic performance and flow loss characteristics of bulb tubular pump
Authors: Wu Jinxin , Pan Weifeng , Cheng Li 
Published: October 2024

Abstract
Bulb tubular pumps used in regional water transfer projects consume substantial power. Optimizing the geometric parameters of tubular pumps is crucial for enhancing efficiency and minimizing hydraulic losses. ANSYS CFX is used to investigate the axial distance between the impeller and the diffuser on the hydraulic performance and flow loss characteristics of the rear-bulb tubular pump, and the numerical simulation results are compared with the experimental data. Then, the entropy production theory is introduced to analyze flow losses. As the axial distance increases, the diffuser’s rectification effect on the flow at the impeller outlet deteriorates, leading to increased flow losses and decreased head and efficiency of the device. Flow losses in the bulb tubular pump are ranked from largest to smallest as follows: impeller, outflow channel, diffuser, inlet channel. The impeller exhibits the highest entropy production ratio, reaching 61.05% at an axial distance of 25 mm. By elucidating the energy loss distribution of each component under varying axial distances, this paper offers insights for the hydraulic optimization design of bulb tubular pumps.
Experimental study on energy and hydraulic performance of the axial flow pumping device with bell-shaped inlet channel
Authors: Shen Fangfang , Xu Xudong , Zhang Hui , Li Wei , Tang Yu 
Published: October 2024

Abstract
Due to the unique inlet design of the axial flow pump device with a bell shaped inlet channel, there is currently insufficient quantitative research on its hydraulic characteristics. This study investigates the hydraulic behavior of a vertical axial flow pumping device equipped with a bell-shaped inlet channel, analyzing various blade angles. Energy, cavitation, runaway, and pressure pulsation characteristics were assessed through meticulous testing on a high-precision test bench. Experimental findings indicate that altering the blade angle of the vertical axial flow pumping device with a bell-shaped inlet channel can influence its overall efficiency to some extent. Moreover, as the pump’s blade angle increases incrementally, the device’s cavitation performance gradually diminishes. Pressure pulsation tests reveal a relatively minor amplitude of pressure pulsation at the impeller outlet, contrasting with a more pronounced amplitude observed at the guide vane outlet compared to the pump outlet. These research results provide valuable insights for the design and optimization of actual pumping stations.
Evaluation of Clogging Potential Prediction Methods in Axial Flow Waterjet Pumps with CFD-DEM
Authors: Minetoma Yuki , Kondo Yuki , Miyagawa Kazuyoshi , Sano Takeshi , Suematsu Junichi 
Published: October 2024

Abstract
Axial flow waterjet pumps propel high-speed passenger vessels by energizing and expelling fluid. In operation, foreign objects may enter, especially in shallow waters, potentially leading to performance decline and damage. Evaluating passage performance is crucial but primarily experimental and computationally costly. Limited research exists on deliberately introducing solids into axial flow pumps due to visualization challenges. Hence, experiments simulated solid substance entry into axial flow pumps, varying particle conditions. High-speed cameras visualized particle behaviour, exploring retention and optimal pump shapes. Additionally, simulations using the Discrete Element Method (DEM) confirmed its utility in predicting foreign object passage, with variations in particle retention across regions noted.
Investigation into the Energy Loss Mechanism of Pump Turbine During the Runaway Process Based on Entropy Production Theory
Authors: Li Yanyan , Guo Pengcheng , Cao Mengjia , Sun Longgang 
Published: October 2024

Abstract
The power-trip of the pump under certain conditions leads to the runaway of the unit, causing dangerous transitional process in pumped storage power stations. This process is characterized by transient hydraulic features like flow separation and vortex structures, which increase hydraulic losses significantly and severely impact unit efficiency and stability. This paper aims to elucidate the mechanism of energy loss due to unstable flow during pump turbine runaway. It focuses on a high-head model pump turbine, examining the transient flow process from pump conditions to runaway conditions. It conducts quantitative analysis of energy loss using entropy production theory, besides, further clarifies the location and causes of hydraulic losses by integrating with internal flow analysis. The results show that a significant high-entropy production zone is captured in the pump braking condition, indicating extremely chaotic internal flow in this area during the runaway transition process. Additionally, throughout the transition process, turbulent entropy production initially increases, then decreases. Turbulent entropy production accounts for more than 80% of total entropy production, indicating that turbulent entropy production dominates throughout the entire transition process. The energy of the water is primarily dissipated within the runner during the runaway process. The maximum proportion is 87%, which is in the pump braking condition. Correlation analysis between flow and hydraulic losses reveals that vortex structure induced by flow separation under off-design conditions is the primary contributor to increased hydraulic losses.
Research on the Internal Flow Characteristics of an Electric Coolant Pump
Authors: Yang Zhengyin , Yang Anlong , Gu Yandong , Zhang Lin , Zhu Dongdong , Zhou Zhiqiang , Ouyang Xili 
Published: October 2024

Abstract
To investigate the internal flow characteristics of an automotive electronic coolant pump, numerical simulations were performed utilizing the ANSYS CFX commercial software suite. The study delved into the velocity distribution, pressure pulsation intensity characteristics, and entropy generation of the electronic coolant pump under varying operational conditions. The findings revealed that with an increase in the flow rate, the coolant flow velocity within the pump also escalated. Concurrently, the separation flow at the trailing edge of the blade diminished, while the flow velocity at the trailing edge of the pressure surface escalated. Notably, the impeller and volute emerged as the primary sites generating pressure pulsations, with pressure pulsation intensity within the pump surpassing that of the design condition in off-design scenarios. Furthermore, entropy generation predominantly manifested at the impeller, volute, and front pump chamber locations, with the impeller exhibiting minimal total entropy generation under design conditions. These insights serve as crucial reference points for optimizing the design of automotive electronic coolant pumps.
Study on the internal flow evolution mechanism and pressure pulsation characteristics of the transient process of variable speed regulation of centrifugal pump
Authors: Li Zhi , Dong Wei , Zhou Chenyu , Li Peixuan , Zhang Haichen 
Published: October 2024

Abstract
In view of the fact that it is not possible to quantitatively analyze any change in the internal flow characteristics of traditional centrifugal pumps during variable speed regulation, numerical computational fluid dynamics (CFD) simulations were carried out in this study to obtain the optimal adjustment range of variable speed regulation. A single-stage IS80-65-160 centrifugal pump is modeled in 3D using Pro/E and ICEM software, followed by CFD simulations. Results are compared with experimental data, showing good agreement. Variable speed adjustments ranging from 0.5-1.0 times the original values are applied to observe changes in internal flow characteristics, such as velocity and turbulent kinetic energy. Pressure and velocity variations in different parts of the pump are studied under varied working conditions. Pressure pulsation frequency domain characteristics are measured at monitoring points in the volute. Findings indicate that as flow rate decreases due to variable speed regulation, velocity decreases linearly, while turbulent kinetic energy decreases quadratically in a uniform distribution. Pressure fluctuations within the volute remain within 0.01 Cp range, but at the tongue, fluctuations can reach up to 0.6 Cp, suggesting an optimal adjustment range within 30% of the rated value.
Visualization experiment of solid-liquid two-phase flow transportation in a jet pump
Authors: Chuanhao Fan , Mengxue Dong , Maosen Xu , Jiegang Mou , Pengfei Han 
Published: October 2024

Abstract
Due to its lack of internal moving components, the jet pump offers widespread application possibilities in solid-liquid two-phase flow transportation. Utilizing high-speed photography, this research established a visual experimental platform for jet pumps, allowing for a detailed study and analysis of the dynamics of solid particles entering, mixing, and being conveyed through the jet pump. The following results were obtained. The introduction of solid phase particles into the jet pump results in decreased pressure ratio and efficiency, yet the general trajectory of change within the pump system remains constant. With decreasing particle size, particles become increasingly susceptible to being entrained and propelled into the jet pump by the high-velocity jet flow. The proportion of particle distribution in the mixing chamber rises as the flow ratio goes up. However, when the flow ratio falls below 0.6, the changes in particle distribution beneath the jet zone of the mixing chamber become insignificant, primarily due to the impact of particle deposition within the suction chamber. A reflux zone is observed in the throat, which gradually shrinks in length as the flow ratio increases.
Applicability of extended vortex identification methods for two-phase separation in multiphase pump
Authors: Wu Xitong , Li Chenhao , Luo Xingqi , Feng Jianjun , Zhu Guojun 
Published: October 2024

Abstract
In the process of multiphase flow transport, there is a slip velocity between phases, which affects the interphase force and leads to the separation of two phases. In order to analyze the flow structure of phases separation motion, the extended vortex identification methods in a multiphase pump is evaluated. The results show that the generation of two-phase separation structure inside the fluid machinery will seriously affect the phase distribution characteristics of the fluid machinery, and then affect the internal flow field and external performance. The extended vortex identification methods can characterize the intensity, location and evolution of two-phase separation in the pump. The research can offer a pertinent theoretical foundation for subsequent flow analysis and design optimization.
Research on the internal flow characteristics of centrifugal pump based on streamlined anti-guide vane
Authors: Ma Jinshui , Li Chenhao , Li Lu , Luo Xingqi , Zhu Guojun 
Published: October 2024

Abstract
Anti-guide vane is part of the radial guide vane in multi-stage centrifugal pump, and the hydraulic loss of anti-guide vane is the dominant factor affecting the performance of radial guide vane. In this paper, the radial guide vane is chosen as the research object, an optimization scheme of streamlined anti-guide vane is proposed based on the arc-shaped anti-guide vane with inlet angle α=25°. The simulation calculation of multi-stage centrifugal pump is drawn using the SST k-ω turbulence model. and the influence of the streamlined anti-guide vane on the hydraulic performance is studied. The result shows that: Under various flow conditions, the head of the multistage centrifugal pump with streamlined anti-guide vanes is higher than that of the prototype. When the flow rate is 1.3Q, the head is increased by 7.2%. and the efficiency is increased by 2.3%. The amplitude of pressure fluctuation of the streamlined anti-guide vane is significantly decreased at each monitoring point compared to the prototype, indicating that the streamlined anti-guide vane weakens the influence of the pressure fluctuation. Furthermore, the streamlined anti-guide vane enhances the pre-swirl of the inlet fluid to the secondary impeller, reduces the impact loss, and improves the pressurization capacity of the secondary impeller.
Optimization of geometrical parameters of positive guide vane for multi-stage pump as turbine based on orthogonal test
Authors: Wang Shicheng , Yang Junhu , Xu Guobin 
Published: October 2024

Abstract
Multi-stage pumps as turbines (PAT) are commonly employed in the petrochemical, coal chemical, and other process industries to recover liquid residual pressure energy. This study focused on improving the performance of multi-stage PAT, specifically targeting the slope of the power-flow(P-Q) curve and hydraulic efficiency at the rated flow point. A two-stage PAT was selected as the research object for this study. According to the relationship between the power and the geometrical parameters of the positive guide vane derived based on the basic equation of the multi-stage PAT, four parameters of the positive guide vane were selected as the test factors for the orthogonal experimental study. A four-factor, three-level orthogonal table of type L9(34) was established. Using Fluent software and the RNG k-ε turbulence model to carry out numerical calculations of constant flow, the results showed that: for the slope of the P-Q curve, the influence of geometric parameter factors of the positive guide vane are in the order of the throat area, the outlet placement angle, the positive guide vanes number, and the base circle diameter; and for the hydraulic efficiency, the influence of geometric parameter factors of the positive guide vane are in the order of the throat area, the positive guide vanes number, the outlet placement angle, and the base circle diameter of the positive guide vane. At the rated flow point, the P-Q curve of the optimized solution decreased by 0.24, resulting in a flatter curve and a 0.3% increase in hydraulic efficiency. There was little change in the vicinity at the rated flow point. The best efficiency point of the optimized scheme is biased toward the high flow rate, the efficiency is increased by 1.85%, and the best efficiency zone is wider. Therefore, selecting appropriate positive guide vane geometry parameters can flatten the P-Q curve, improve internal flow, and enhance hydraulic efficiency.
Analysis of variable speed operating range of centrifugal pump with large flow and wide head variation
Authors: Zheng Yang , Tian Yajuan , Zhang Chiye , Wang Xin , Meng Long 
Published: October 2024

Abstract
The advantages of variable speed centrifugal pump include its broad operating range, wide operating efficiency zone, high operational stability, and regulative characteristics of input power. When pump station has characteristics such as large flow rate changes, large pump head changes, the conventional fixed speed centrifugal pump cannot meet requirements of safe and stable operation under characteristic pump conditions. In order to ensure the safe and stable operation of the pump station within the operation range, the variable speed operation strategy of centrifugal pumps is adopted to enhance its wide amplitude adjustment capability and efficient operation. This paper uses an 8MW centrifugal pump with wide head range in China to analyze the factors that influence the operating range of pump unit in detail. The results indicate that the variable speed pump unit’s safe and effective operating range is determined by the cavitation margin, hump margin, speed range, and pump maximum input power. The hydraulic design can improve the hump safety margin and cavitation characteristics of the operating zone, and then expand the operating range of the pump unit. Meanwhile, increasing the static suction head, reducing the hump margin, controlling pump head amplitude, and appropriately increasing the maximum input power limit are the best ways to extend centrifugal pump’s operating range and improve its adjustable capability. The results can provide reference for parameter selection and hydraulic design of large variable centrifugal pump in the future.
An Improved Grey Wolf Optimizer(IGWO) algorithm for optimization of centrifugal pump with guide vane
Authors: Jian Dong , Jinling Lu , Wuke Liang , Wei Wang , Gaigai Ai 
Published: October 2024

Abstract
To improve the hydraulic performance of a centrifugal pump with guide vane, an improved grey wolf optimizer (IGWO) algorithm is proposed. First, the IGWO algorithm enhances the diversity and global exploration of the initial population with optimal Latin hypercube sampling. Then, the convergence factor is improved by combining the Tanh function to meet the needs of complex non-linear optimization problems. Finally, a search mechanism that enhances population communication is constructed and combined with a mutation-driven search scheme to improve the ability to avoids the local optima traps. The results show that IGWO algorithm has obvious advantages in convergence speed and robustness when dealing with complex non-linear optimization problems. Additionally, satisfactory results are achieved in the application of centrifugal pump optimization. The efficiency of optimized pump reaches 87.8%, which is 1.2% higher than that of the original pump. The anti-cavitation performance of the centrifugal pump is enhanced by improving the distribution of blade inlet attack angles. The vortex area inside the optimized pump impeller is reduced over a large area, and the operating stability of the pump, the matching between the impeller and the guide vane, and the flow characteristics in the guide vane domain are all improved.
Study on the influence of guide vane opening on pressure pulsation of pump-turbine under zero flow pump condition
Authors: Yi Chuanbao , Lu Yonggang , Li Xiji , Zhao Yun , Sun Chuanzhen , Wang Zhengwei 
Published: October 2024

Abstract
Reversible pump-turbine is the key equipment of energy conversion in large pumped storage power station, and it is the core of stable operation of power station. Under the pump condition, the internal pressure pulsation law of the pump-turbine has an important influence on the stable operation of the pump. In order to study the pressure pulsation characteristics of pump-turbine in pump mode under zero flow condition, this study carried out unsteady numerical simulation on three kinds of guide vane openings, and analyzed the amplitude frequency characteristics of pressure pulsation in turbine under different head and the influence of internal flow characteristics on pressure pulsation. The research shows that in the pump mode, when the guide vane opening of the turbine increases, the influence of the blade frequency and the shaft frequency on the vaneless area increases, resulting in the maximum pressure fluctuation amplitude in the vaneless area under the pump condition, especially when GVO = 19 °. At the same time, due to the influence of dynamic and static interference, the larger turbulent kinetic energy appears in the vaneless area and the connection between the guide vane flow channel and the runner flow channel, resulting in an increase in hydraulic loss. Both the experimental and simulation results show that the guide vane opening of 19 ° should be avoided to reduce the hydraulic loss in the vaneless area when the turbine is operated under the zero flow pump condition.
Optimization Design of Bionic Leading-edge Protuberances on Horizontal Axis Wind Turbine Blades
Authors: Wei X T , Li D Y , Zhang R Y , Chang H , Wang H J 
Published: October 2024

Abstract
The complex operating environments of horizontal axis wind turbines has made the phenomenon of blade flow separation more obvious. As a passive flow control method, the bionic humpback whale leading-edge protuberances have been shown to effectively enhance the performance of the wind turbine. This study employs a multi-objective genetic algorithm and Computational Fluid Dynamics method to analyse the impact of leading-edge protuberances on the aerodynamic performance and flow characteristics of the blades. The results indicate a significant improvement in blade performance after optimization in the wind turbine’s output power. The streamwise vortices generated by the bionic protuberances not only reduce the suction surface pressure, but also suppress the spanwise flow over the blade surface. The length of the flow separation Region is reduced from 0.410 to 0.368 radius. In the process of wind speed change, the tangential forces on the bionic blade exhibit a wave-like variation. The bionic protuberance alters the pressure coefficient of the position. Compared with the original blade, the pressure coefficient of the trough sections on both sides of the bionic blade protuberance is improved. In this study, the bionic protuberance applied to the leading-edge of horizontal-axis wind turbine blades is proposed for the first time, and holds practical value for guiding practical applications.