bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Maximum Airfoil Camber Position on Hydrofoil Cavitation Performance
Authors: Yang Chenglin , Tang Fangping 
Published: October 2024

Abstract
This study’s primary goal is to investigate how various airfoils’ maximum camber positions affect hydrofoil cavitation performance. Through numerical simulation, the cavitation low properties of hydrofoils with various maximum camber positions are compared. The accuracy of the modi ied turbulence viscosity and SST k-ω turbulence model on the temporal and spatial evolution characteristics of cavitation near the hydrofoil is evaluated by combining it with the model test. Analysis is done on the cavitation low ield of four airfoils at two distinct design angles of attack (+4° and +6°) with varying maximum camber locations (fmax = 35%C, 40%C, 50%C, and 60%C). The indings indicate that at 35%C, the hydrofoil’s maximum camber position has improved cavitation performance. The hydrofoil’s cloud cavitation evolution time is shorter than that of the original hydrofoil, and during the same time period, more cavitation is generated. The lift-to-drag ratio and lift coef icient of the cavitation low ield are signi icantly improved at both angles of attack. At the same time, the vorticity distribution and entropy generation distribution can be effectively reduced under the design angle of attack and high angle of attack cavitation, and the hydraulic loss in the cavitation low ield can be reduced. This research can serve as a guide for optimizing the hydrofoil’s cavitation performance and designing the impeller of the axial low pump that follows.
Study in Gas-Phase Agglomeration Characteristics of Spiral Flow Gas-Liquid Multiphase Pump
Authors: Han Wei , Guo Xuanchen , Feng Huiming , He Chunpei , Zhang Yukun , Xie Wenqi 
Published: October 2024

Abstract
The spiral flow gas-liquid mixed transport pump experiences gas phase accumulation in the impeller flow passage, leading to blockage and a decrease in pumping performance. To understand the rules and mechanisms of gas phase aggregation in the spiral flow gas-liquid mixed transport pump, numerical calculations based on the Eulerian multiphase flow model and SST k – ω turbulent flow model were conducted. The effects of different gas volume fractions, speeds, and liquid phase viscosities on the pump were explored, and the external characteristics, flow characteristics, and gas phase aggregation processes in the impeller were analysed for these three variables. The results indicate that the head and efficiency of the pump gradually decrease with increasing gas volume fraction and liquid phase viscosity, while they increase with increasing speed. When the liquid phase viscosity changes from pure water to 50 times its viscosity, the gas phase aggregation at the impeller outlet decreases, resulting in reduced pressure and a smaller vortex region. The relative gas phase aggregation degree λ decreases from 0.5 to almost 0. When the gas volume fraction increases from 20% to 60%, the gas phase aggregation at the impeller outlet increases, the pressure difference between the impeller hub and the rim increases, and the vortex region expands, leading to an increase in λ by 8 times. When the speed increases from 3000 rpm to 5000 rpm, the gas phase aggregation at the impeller outlet increases, the pressure increases, and the vortex region expands, resulting in a 16-fold increase in λ.
Application of intelligent algorithms in optimal operation of pumping stations
Authors: Sun Xiaoyu , Feng Xiaoli 
Published: October 2024

Abstract
An optimal operation model of pumping stations is established in this paper, with the minimum energy consumption of the pumping station as the optimization objective, considering the constraints of the pumping station operating head, flowrate of the pumping station and so on. Simulated annealing is introduced into genetic algorithm, particle swarm optimization, wolf pack algorithm and grey wolf optimization to solve the model. The minimum value, average value, relative standard deviation of the objective function and infeasibility of constraint conditions are selected as the evaluation indexes of the algorithms performance. The calculation results show that simulated annealing ensures that the intelligent algorithms can find the optimal solution in the feasible solution space and avoid them falling into local optimization. The operation schemes obtained by solving the example model with the improved algorithm can reduce the energy consumption of the pumping station by 5.759%∼6.682%, which provides guidance for the operation schemes of the example pumping station. The results can be further applied in other pumping stations.
Effect of Gasket Wear Rate on Hydraulic Performance and Internal Flow of Multistage Centrifugal Pump with Floating Impellers
Authors: Bian Junjie , Gu Yandong , Wang Dongcheng 
Published: October 2024

Abstract
The sealing gaskets of multistage centrifugal pumps are prone to wear during operation. This study investigates the influence of gasket wear rate on hydraulic performance and internal flow field through numerical simulations. As the wear rate of the gasket increases, both the efficiency and head coefficient of the pump gradually decrease. When the gasket is completely worn out, the efficiency decreases by 5.6% and the head coefficient decreases by 9.5% compared to the unworn gasket condition. Analysis of the internal flow field reveals that the front side chamber is most significantly affected by gasket wear. As the gasket wears, the flow velocity within the front side chamber increases gradually, and the high-entropy production zone expands, thereby affecting the hydraulic performance of the pump. The findings of this study provide practical engineering insights for enhancing the operational performance of multistage centrifugal pumps.
Numerical simulation on energy characteristics of pump-turbine under pump condition
Authors: Chen Zhenyu , Li Chenhao , Luo Xingqi , Zhu Guojun 
Published: October 2024

Abstract
To investigate the energy characteristics of the pump turbine in pump mode, we selected the pump turbine as the research object and employed the SST k-ω turbulence model to conduct three-dimensional steady numerical simulations of the internal flow field of the pump turbine under several typical flow conditions. Our findings indicate that the unit’s energy loss is primarily concentrated in the runner and guide vane areas. In the small flow condition area, the energy loss of the draft tube basin cannot be ignored, while the energy loss in the stay guide vane and spiral casing areas is relatively small due to their low flow velocity. As the flow rate decreases, the energy loss in the draft tube, runner, and guide vane areas increases continuously. Additionally, complex flows such as vortex flow and backflow appear in the double-row cascade flow channel, which obstructs the flow channel and increases dissipation energy. In typical flow conditions, the energy loss in the draft tube, runner, and guide vane areas is a significant factor contributing to the decrease in head.
Research on Rapid Detection Method of Cavitation State of Water jet Propulsion Pump Based on Multi-source and Multi-feature of Acoustic Emission Signal and Bayesian Network
Authors: Feng Chao , Zhu Hualun , Chen Beibei , Yang Mengzi 
Published: October 2024

Abstract
Cavitation prevents the conversion of internal dynamic and pressure energy in a water jet propulsion pump and causes erosion of flow passage components. Acoustic emission is a non-destructive test method for instability signals. Based on the incipient mechanism and development process of cavitation, three acoustic emission signal feature parameters (ring counting rate, energy release rate, Hurst index) are proposed to define the cavitation state utilizing the waveform pattern and signal self-similarity. The multi-source and multi-feature cavitation identification model of acoustic emission signals is established through cavitation simulation, multi-monitoring point acoustic emission signal testing, and feature parameter extraction, and a large number of probabilistic trainings are carried out using Bayesian network, resulting in a fast cavitation state identification method based on acoustic emission signals. The research results have important practical engineering application significance for the prediction of cavitation resistance, real-time dynamic monitoring of cavitation phenomenon and prevention of cavitation damage.
Researches on the Dynamics of the Cavitation Bubble Near the Rigid Wall with a Hole
Authors: Zhao Zi-Yi , Zi Dan , Yao Zhi-Feng , Sun Yu-Rong , Qiang-Zhong  , Wang Fu-Jun 
Published: October 2024

Abstract
When cavitation bubbles collapse near the wall, the micro-jet and shock wave causes damage to the surface of hydraulic machineries. In severe cases, this damage may lead to structural harm. This paper focuses on the cavitation bubble evolution process near the rigid wall with a hole by the experiment and numerical simulation. The space-time morphological characteristics of the bubble at distinct stages (the growth stage, the collapse stage and the rebound stage) are described for the situation of γ=0.7. The distribution of the pressure and the velocity fields at different stages are elucidate. At γ=0.7, a shock wave with a maximum value of the pressure approximately to 14MPa is emitted when the bubble collapses. Meanwhile, a micro-jet attaining a maximum velocity of about 129 m/s is created. Notably, the micro-jet induced by the collapse of a bubble near the rigid wall with a hole is away from the wall, which is different from the micro-jet caused by the collapse of a bubble near the rigid wall.
Fatigue failure analysis of bulb turbine sealing gland bolts based on vibration signal
Authors: Yin Xinyuan , Liu Zhong , Li Bajun , Liu Bo , Zeng Zuopeng , Li Le 
Published: October 2024

Abstract
Aiming at the issue of fatigue fracture of the sealing gland bolts, this paper takes a bulb tubular turbine with frequent breakage of sealing gland bolts as the research object, establishes a finite element model of the sealing gland, and collects the vibration signals of the sealing gland under three common working conditions through vibration tests. Based on the vibration signal data and dynamic analysis, the vibration fatigue load spectrum of the sealing gland is calculated, and then the fatigue analysis of the sealing gland bolts is carried out. The results revealed that vibration of the sealing gland in the -X direction is much more severe than that in the +X direction, and the minimum fatigue life of the sealing gland bolt group in the - X direction is much shorter than that in the +X direction. Comparing the fatigue analysis results of the ±X-direction sealing gland bolts under different working conditions, it is found that under the same test water head, the service life of the sealing gland bolts under stable operation of 15MW is longer than that of 10MW and 20MW. It is recommended to take measures to reduce the problem of excessive vibration in the -X direction of the unit.
Identification and monitoring of wall-attached vortices in open pump intake based on continuous wavelet transform
Authors: Yu Kai , Huang Xianbei , Guo Qiang , Jin Guanqi 
Published: October 2024

Abstract
Wall-attached vortices in pump intake commonly appear and has a negative impact on the safety and efficiency of the pumping stations. The monitoring of these vortices are crucial for safe operation of the pump intake. In this paper, SAS model were performed on a pump intake with an axial-flow pump installed in the suction pipe. Two submergences (500mm and 600mm, namely 3.33DL
and 4DL
) and three flow rates (0.8Qd
, 1.0Qd
, 1.2Qd
) were studied. The continuous wavelet transform (CWT) was applied to the pressure signals near the vortices, showed the similarity of time-frequency characteristics at different points under the same flow rate and water level condition.. It was found that the generation and development were slower for larger submergence. At low flow rate 0.8Qd, the flow angle shows larger deviation from 90°, which causes the higher CWT power. By analyzing the powers of dominant frequencies at all the monitor points, it is recommended to set the monitor points within a rectangle that is 0.77DL and 0.97 DL from the back wall and side wall respectively. The conclusions are suitable for similar intakes under similar conditions with 1.2Qd
of the pump. Also, they can be good guidance for more generalized open pump intakes.
Internal flow analysis and design optimization of a membrane oxygenator
Authors: Jian Meng , Zheng Kexin , Zhang Mingkui , Huang Jianbing , Luo Xianwu 
Published: October 2024

Abstract
The membrane oxygenator is an essential component in the Extracorporeal Membrane Oxygenation (ECMO) system to offer temporary support to the respiratory system. This study aims to optimize the hemodynamic performance and reduce the thrombosis risk of a membrane oxygenator prototype using computational fluid dynamics. Numerical simulations of steady laminar flow in a full-scale oxygenator prototype (model 1) and two optimized structure Models 2 and 3 at flow rates of 5∼7L/min are carried out using the porous media model. Flow-field-based hydraulic performance indicators and the thrombus risk indicator of the three models are compared extensively. Detailed internal flow analysis revealed that adverse flow states such as insufficient flow circulation in the inlet shunt cone zone, large flow separations at the top corners of heat exchangers, and intensive flow impingement at the exit elbow tube are notably improved in the optimized model 2 and 3. The improvement is more significant at high flow rates. Performance parameters quantitatively validate the effect of optimized configurations. Specifically, at a flow rate of 7L/min, the flow uniformity indexes for the original model at the shunt cone exit increase from 0.884 to 0.923 and 0.890 in the two modified models. The total pressure loss is reduced by over 14%, and maximum wall shear stress is notably reduced from 241.46Pa to 135.9Pa. Additionally, the optimized models exhibited lower thrombus risk. The optimized designs emphasize the importance of smooth transitions between cross-sections and minimizing abrupt changes in flow direction. The employment of flow-field-based parameters allows for the establishment of the relationship between geometric and performance parameters to guide effective design optimization and ensure the safe clinical operation of oxygenator prototypes.
Numerical analysis of cavitation characteristics on front surfaces of different Pelton turbine buckets
Authors: Zishi Liu , Jie Liu , Quanwei Liang , Yexiang Xiao , Yushu Zhou , Haijun Li , Zhengshu Liu , Zongqiu Hu , Qingpin Du 
Published: October 2024

Abstract
Cavitation may occur in the runner bucket of the Pelton turbine, which could lead to cavitation erosion on the bucket surface. In this paper, three types of bucket were selected to carry out transient multiphase flow simulation at the same operating point of a model Pelton turbine. The hydraulic performance and cavitation characteristics of different buckets were analysed. The 3 bucket models were developed for Pelton turbines operating under the middle-high and the high-water head range, respectively. Results showed that the participation of cavitation model in simulation would slightly affect the working process of the bucket. The cavitation on the front surface of three buckets all happened at the beginning stage of jet inflowing the bucket, among which bucket C had the most serious cavitation on the front surface. This work showed different cavitation characteristics among various types of bucket, and the relevant result suggested comprehensive design considering cavitation characteristics should be done on the front surface of the bucket for a specific range of water head.
Modal characteristics analysis of a variable-speed pump-turbine rotor system: a perspective of resonance
Authors: Wang Lei , Yu Shuang , Wang Zhengwei 
Published: October 2024

Abstract
The safety and stability of the rotor system is crucial to the pump-turbine unit. The present paper analyzed the modal characteristics of a variable-speed pump-turbine rotor system based on the rotor dynamics theory and FEM method. The results show that the bending mode of the rotor system exhibits the forms of forward whirling (FW) and backward whirling (BW). The added mass effect will reduce the natural frequency of the rotor system, and it is more obvious for the torsional mode Torsional 1. In addition, the critical speed analysis shows that both the critical speed of the dry mode and wet mode of the rotor system is greater than 700rpm, which proves the safety of the unit. The results of the analysis can be used as a reference for the optimized design of similar variable-speed pump-turbine rotor system, which is conducive to the improvement of the reliability and life of the rotor system.
Numerical simulation of unsteady cloud cavitation in an orifice nozzle by a compressible gas-vapor/liquid mixture cavitation model
Authors: Peng Guoyi , Onishi Taihei 
Published: October 2024

Abstract
Focused on the behaviour of unsteady cloud cavitation in a submerged orifice nozzle, this work presents a numerical investigation by using a compressible gas-vapor/liquid mixture cavitation model. The mean flow of the two-phase mixture is calculated by URANS for compressible fluid and the intensity of cavitation is evaluated by the gas volumetric void fraction considering the effect of fluid compressibility varying with phase change. Water jets issuing from a submerged orifice nozzle are investigated under different cavitation conditions. Computation results are compared with experiment data and the validity of computation is confirmed. The periodical shedding of cavitation clouds is captured reliably. Numerical simulations reveal that a leading cloud principally split by the shear flow and a subsequent cloud detached by the re-entrant jet are successively shed downstream, and they coalesce over the range of approximately x/d ≈ 2∼3. This process is repeated and the flow rate coefficient pulsates periodically under the effect of cavitation clouds.
Large Eddy Simulation of an impinging Jet for Cooling of Blades
Authors: Ou Y Q , Lai H X 
Published: October 2024

Abstract
The impinging jet shows extremely high performance in local blade cooling and has been widely applied. In this study, high precision Large Eddy Simulation (LES) was employed to simulate compressible fully turbulent impinging jet under specific conditions, using three subgrid-scale (SGS) models - the Smagorinsky model (SM), the Coherent-structure Smagorinsky Model (CSM), and the Selective Mixed Scale Model (SMSM). The predictive accuracy and computational efficiency of the three SGS models were evaluated. Compared with existing DNS and experimental results, the results indicate that there is no significant difference among the three models in computational efficiency. However, subgrid models have a crucial impact on heat transfer. The SMSM model, which utilizes small-scale turbulence information, can better simulate the heat transfer in the impingement region compared with the SM model and the CSM model.
Stability impact on wind turbine blades trailing edge from bonding zone modelling methods
Authors: Zhao Jing , Mao Zhongyu , Zhou Wenming , Feng Yongguo 
Published: October 2024

Abstract
The trailing edge of wind turbine blade will undergo a large deformation under the action of load, resulting in a higher risk of damage and failure. The finite element analysis modeling method directly affects the simulation result, furthermore impacts the result of blade structure design. Therefore, it is necessary to find out a modeling method, which is capable to reflect the stability of bonding regions more accurately. This paper aims to discuss the influences of different finite element modeling methods on the buckling stability of blade trailing edge. The influences of shell element, tetrahedron element and hexahedron element on the blade stiffness are considered. The bonding region were simulated separately by combining shell element with bonding web, shell element with tetrahedron element and shell element with hexahedron. The influences of different bonding region modeling methods on the trailing edge buckling factor were analyzed by using the eigenvalue buckling analysis method of finite element. The simulation results provided data support for the future validation of the blade trailing edge bonding area modeling method. The results show that, the tetrahedral mesh provides a higher stiffness, followed by the hexahedral mesh, and the adhesive web form has the smallest stiffness. In order to simulate the more realistic stiffness of the adhesive area at the trailing edge of the blade, adhesive web plates can be built in the flange area of the blade root and the core material area of the trial adhesive mold; The direct bonding area can be simulated employing the hexahedron mesh; The tetrahedral mesh has high stiffness and is not suitable for modeling the adhesive area at the trailing edge. Blade simulation modeling can flexibly use different adhesive forms according to actual situations, ensuring the reliability of the simulation model.
Optimization of impeller parameters for hydrodynamic turbine based on multi-objective orthogonal test design
Authors: Wang Chengpeng , Wang Shenghui , Xiao Yexiang , Sun Xiang , Tian Xiugui , Luo Xianwu 
Published: October 2024

Abstract
The inherent instabilities within the structure of turbine-type energy recovery integrated machine (TT-ERIM) can compromise its smoothness and longevity, potentially leading to malfunctions. The dynamics of the dual-side impeller of TT-ERIM is research using computational fluid dynamics software CFX and manipulating the inlet flow rate. The pressure pulsation and radial force on each side under different flow conditions, and their impact on the hydraulic performance of the impeller and volute are compared and evaluated through unsteady numerical calculations. The results show that the pressure fluctuation pattern of a hydraulic turbine impeller is suboptimal at low flow rates, escalating at conditions below the rated flow. Conversely, the pressure fluctuations of the turbine impeller remain consistent and are slightly reduced with excessively high flow rates. Generating a negative pressure zone in the turbine impeller indicates an uneven overall pressure distribution. This research provides a theoretical platform for enhancing the TT-ERIM operational stability.
Design and analysis of hundred-meter wind turbine blade trailing edge based on finite element method (FEM)
Authors: Chai Hongmei , Luo Xiaojun , Li Peixin , Mao Zhongyu , Li Meizhi , Zhou Wen Ming , Feng Yongguo 
Published: October 2024

Abstract
The trailing edge region of composite wind turbine blades usually has a large deformation under wind load and the accidents caused by the damage of blade trailing edge accounts for a large proportion among blade accidents. With the development of large blade size, higher requirements are put forward for the stability of wind turbine blade trailing edge. Therefore, the trailing edge region is critical in the design of blade. A detailed study of the design and analysis for wind turbine blade trailing edge region was carried out in which the structure stability was regarded as the key. The influence of auxiliary spar cap and auxiliary spar web on the stiffness distribution and stability of the trailing edge were studied based on focus and finite element method (FEM). The respiratory effect of different structures due to deformation were analyzed and compared. The results showed that the structure of the auxiliary spar cap and auxiliary spar web can significantly increase stiffness, stability and decrease respiratory deformation at the trailing edge of blade compared to the traditional three webs structure. The structure of auxiliary spar and auxiliary spar web is the best design scheme for hundred-meter composite blade trailing edge.