bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization Analysis of Head Cover Structure of High Head Pump Turbine
Authors: Hong Zhang , Shihai Huang , Junpeng Zhou , Min Song , Weibin Song , Yanmei Ma
Published: June 2024

Head cover is one of the key components of the pump turbine. Its stiffness and axial stiffness have an important influence on the safe and stable operation of the unit. The structure of head cover is related to the design pressure. In this paper, the structure of head cover of the high head pump turbine is optimized, and the strength and axial stiffness of head cover before and after optimization was analyzed by finite element method. The results show that the optimized head cover is better than the axial stiffness of head cover before optimization.
Technical investigation of the ternary pumped storage hydro units with ultra-high-water head
Authors: Dongkuo Li , Zishi Liu , Hongping Min , Yexiang Xiao , Zhonghua Gui , Xiaodong Wang , Hao Lin
Published: June 2024

This paper introduces the ternary pumped storage hydro unit technology and its development status, discusses the technical characteristics of the ternary unit, and looks forward to the broad application prospect of the ternary unit technology in the ultra-high head pumped storage power station. The main technical advantage of the ternary pumped storage hydro unit by using the Pelton turbine as the turbine component is that the hydraulic short circuit operation mode of the combined operation of pump and turbine can realize the smooth adjustment of the input power of the unit pumping condition. In addition, the conversion time between working conditions is greatly shortened compared with the conventional reversible pumped storage unit, thus greatly enhancing the power grid’s ability to absorb and adjust new energy.
Research on the effect of anti-guide vane inlet Angle on the performance of multistage centrifugal pump
Authors: Chenhao Li , Lu Li , Xingqi Luo , Xitong Wu , Guojun Zhu , Jianjun Feng
Published: June 2024

Anti-guide vane is the component that converts energy and diversion flow in multistage centrifugal pump and its hydraulic loss is the main factor affecting pump performance. In this paper, the multistage centrifugal pump with radial guide vane is taken as the research object. Based on α5
=35° inlet angle of prototype anti-guide vane, two optimization schemes of reducing and increasing the inlet angle are proposed to obtain α5′=25° and α5′′=45°. The SST turbulence model is used to simulate the centrifugal pump before and after optimization. The internal flow velocity characteristics, blade load distribution and pressure pulsation characteristics of the multistage centrifugal pump anti-guide vane were studied. The results show that under large flow conditions, the pump head and efficiency are increased by 4% and 2.66% respectively. And the flow loss in the anti-guide vane is reduced by 6.02%, which greatly improves the unstable flow caused by the impact separation at the anti-guide vane inlet. The blade load increases with the decrease of the anti-guide vane inlet angle, and the pressurization benefit of anti-guide vane is the largest when α5′=25°. The vibration amplitude of pressure pulsation is the largest at the anti-guide vane outlet, and the amplitude increases with the decrease of inlet angle. The research results can provide reference for the optimal design of the multistage centrifugal pumps anti-guide vane.
Numerical and experimental study of tip leakage vortex structures and dynamics in a mixed-flow waterjet pump
Authors: Gong B , Zhu H L , Chen X H , Yin J L , Li N , Wang D Z
Published: June 2024

Driven by the pressure difference between pressure side and suction side, the tip leakage flow (TFL) and forms the tip leakage vortex (TLV), which interact with main flow and leads to instability of flow as well as cavitation in a mixed-flow waterjet pump. In this work, the characteristics of TLV are investigated by experiment based on high-speed photography (HSP) and the numerical simulation. The TLV trajectories predicted by numerical simulation’s shows a good agreement with the experiment test results. Cavitation of the TLV core due to low pressure forms a TLV core cavitation trajectory line. The start position of TLV trajectories and the relative angle between the TLV trajectory and the blade are significantly affected by the blade tip loading. The unsteady primary tip leakage vortex (PTLV) evolution process can be summarised in three stages of splitting, developing, and collapsing.
Numerical Investigation of Impeller Parameters on the Performance and Internal Flow Characteristics in Regenerative Flow Pumps
Authors: Tang Deli , Lu Yi , Li Qianqian , Ge Jian , Miao Xinting
Published: June 2024

As a particular vane pump, regenerative flow pump (RFP) is not only featured by relatively high head under low flow rate, but also is characterized by compact volume and simple structure. However, the efficiency of RFP is quite low. For the purpose of improving RFP’s hydraulic performance and internal flow, this paper investigates the influence of the matching relation between impeller diameter and height on RFP’s performance. Two cases through changing impeller’s diameter and height are designed and compared. The results show that, as impeller’s diameter increases while keeping the blade’s radial length constant, RFP’s head and efficiency are improved, and the best efficiency point (BEP) shifts gradually from lower flow rate to larger flow rate. Additionally, the ratio of the flow rates at BEP is approximately equal to the ratio of the blade’s middle diameters. On the other hand, as impeller’s height increases, the BEPs among different pump models stay in same flow rate, and there is always an optimal impeller’s height for this RFP model to achieve optimal performance. Finally, the pressure distribution, velocity distribution and mass exchange of different models are analysed to reveal the differences.
Optimization of Centrifugal Pump Impeller Based on Neural Network and NSGA-II Algorithm
Authors: Wei Chen , Wensheng Ma , Lei Wang , Meng Zhang , Qiang Zhang , Kaizi Huo
Published: June 2024

This article focuses on the multistage centrifugal pump secondary impeller as the research object, and the two performance parameters of head and efficiency are taken as the optimization objectives. Firstly, the range analysis of significant influence degree of impeller geometric parameters was carried out by partial factor test method. The blade inlet angle at the front and rear cover boards of the impeller, blade outlet angle and blade wrap angle as the optimization variables, two optimization schemes with different blade numbers were proposed. On this basis, the optimal Latin hypercube sampling method was used to extract samples from the two schemes, CFD technology was used to calculate the corresponding target value of each sample, BP neural networks with different structures were used to train the samples, and the agent model with the highest prediction accuracy was optimized as the population evaluation function of NSGA-II algorithm to search for optimization. The results show that the pump performance parameters have been improved after optimization of Scheme II, and the flow of the internal flow field conforms to the law. Finally, through the experimental verification, the optimized centrifugal pump head and efficiency increased by 3.21m and 3.05%.
Influence of impeller energy dissipation characteristics of multi-blade axial flow pump impeller by the cascade density
Authors: Zhao Sen , Yang Congxin , Guo Yanlei , Yingxiang Mo , Haoyu Cui , Lv Tianzhi
Published: June 2024

This paper investigates the influence of cascade density on energy dissipation in the impeller of a multi-blade axial-flow pump. Three-dimensional transient numerical simulations were conducted using the SST k-ω turbulence model for impeller schemes with different cascade density, corresponding to different blade chord length and pitch. Entropy production theory was applied to locate the regions with high energy loss in the impeller. The relationships between local entropy generation, energy loss, and unsteady flow were analyzed for different cascade density. The results indicate that impeller entropy output of the multi-blade axial-flow pump is highly consistent with the head loss during testing. Turbulence dissipation accounts for more than 50% of the total energy loss, followed by wall friction, while direct dissipation is the smallest contributor. The relative loss of the impeller can be minimized by decreasing the number of blades or increasing the blade chord length. By comparing energy dissipation in blade rotation with different chord length and pitch, it is found that turbulent dissipation ability can be controlled more effectively by changing chord length, while the ability of direct dissipation can be controlled more effectively by changing the pitch.
Study on the pulsation and fluid-structure coupling characteristics of rotating parts of vane type mixed-flow pump
Authors: Jin Yan , Xue Ying , Tang Fangping
Published: June 2024

Vane type mixed flow pumps (VTMFP) are widely used in water conservancy engineering, with a wide range of head applications. The impeller is the core component of the pump unit, and its internal flow and hydraulic excitation force affect the safe and stable operation of the unit. Aiming the pulsation characteristics inside the impeller, the VTMFP under different conditions is studied to examine the deformation and stress distribution by CFD, and the simulated results agree with the test data. The simulated results indicate that the impeller blade passing frequency consistently dominates the impeller inlet under various operating conditions. Furthermore, it is observed that the impeller rotating parts experience the highest levels of stress and deformation at low flow rate. The distribution of the equivalent force decreases from the hub to the shroud, while the deformation displacement decreases from the impeller shroud to the hub. In light of these findings, it is recommended that the design process takes into consideration the stress concentration near the blade root and the deformation at the blade edge.
Expression and prediction of pump and pumping station characteristics
Authors: Yan Dengfeng , Feng Xusong , Li Yanjun , Lu Weigang , Chen Songshan
Published: June 2024

According to the relevant literature of pumps and pumping stations and the expression and conversion method of pump efficiency and pump cavitation proposed by the author, through further careful mathematical deduction, the expression of pump and pump device characteristics is proposed. The proposed expressions for centrifugal pumps (and volute type mixed flow pumps) and axial flow pumps (and guide vane type mixed flow pumps) are applicable to both pumps and pump units; it is applicable not only to models, but also to similar prototype pumps and prototype pumping units of any diameter and parameters. The research and realization of performance expression of pumps and pump devices have great theoretical significance and practical application value for improving the design level of pumps and pumping stations and for accurately predicting the characteristics of pumps and pumping stations.
Optimization of Cavitation Performance of High-Speed Centrifugal Pump Based on the Meta-Model of optimal Prognosis
Authors: Wang Xiao-Hui , Zhang Kai , Miao Sen-Chun , Yang Jun-Hu , Shen Zheng-Jing
Published: June 2024

Using a specific type of high-speed centrifugal pump as an example, this study conducted a parameterized optimization design on geometric parameters of the impeller’s flow path. A response sample space was generated with the flow path geometric parameters as input and pressure increment and cavitation volume as output. Based on the Meta-Model of optimal Prognosis, the optimal surrogate model was fitted, and a global sensitivity analysis was conducted. The results indicated that the impeller’s inlet edge parameter and mid-curve parameter had a significant impact on the pressure increment and cavitation volume of the pump. Using a genetic algorithm, the optimal flow path geometric parameters were obtained, and numerical simulation methods were applied to verify the obtained parameters. The results showed that after optimization, the pressure coefficient of the centrifugal pump increased by 0.035, and the cavitation performance improved by 22.28%. The impeller cavitation area and void volume were significantly reduced, and the flow path pressure distribution and flow state were improved.
Study on the volute optimization and mechanism of vortex loss reduction for a centrifugal fan
Authors: Wang Wei , Wang Junlong , Cu Tingting , Zhang Lefu , Lu Jinlin , Feng Jianjun , Luo Xingqi
Published: June 2024

In order to reduce the flow loss in the volute and improve the efficiency of the centrifugal fan further, a new type volute with a diffusion profile was designed and optimized. The effects of diffusion angles were clarified by using numerical simulations and the method of design of experiment. The mechanism of vortex loss reduction of the diffusion-type volute was revealed. The results show that diffusion-type volute can reduce the flow loss in the volute by 30.8% compared with the original volute, and increase the efficiency of the fan by 2.24%. Parametric studies show that the diffusion angle of front disc has a great influence on the efficiency of the fan, and the effect of diffusion angle of rear disc is relatively less. Mechanism analysis shows that the diffusion-type volute can greatly reduce the vortex strength in the volute, especially eliminate the high-intensity vortex near the volute tongue. As a result, the volute loss is remarkably reduced. In addition, the diffusion-type volute can effectively reduce the amplitude of pressure fluctuation in terms of shaft frequency, characteristic frequency and broadband signals in the volute.
Design method and flow analysis of a mixed flow pump based on blade load control
Authors: Liu Demin , Lu Yangping , Tan Lei , Tang Ruoyu , Yan Ming , Wang Zhichao , Ding Xiaoli
Published: June 2024

Mixed flow pumps are commonly used due to their wide operating range. Load distribution is the key parameter of the inverse design of mixed flow pumps. In this study, an inverse design method using a quadratic function to control the blade load distribution is introduced to design a mixed flow pump. The hydraulic performance of the pump is calculated using numerical simulation, and then the internal flow is analyzed. The results show that the pump designed by this method has a high efficiency at the designed point and a wide operating range. The flow field is symmetrical along the circumference and varies uniformly along the impeller inlet to the impeller outlet. No flow separation and no unfavourable low-pressure area appear.
Research on the pitching hydrodynamic performance of pump-jet propelled submersible
Authors: Han W , Hou Y Y , Zhang T , Dong Y F , Xing Y F , Yang Y B , Bai L , Zhang Y K , Yang T , Zhao L L , Xue T Q
Published: June 2024

Most of the current research in the world on the dynamical characteristics of pump-jet propelled submersibles has focused on the dynamic response of non-vector propulsion. However, the dynamics characteristics of water jet vector propulsion by external bypass excitation have been neglected. Therefore, this paper explores the variable vector deflection angle-controlled pitching motion in the vertical plane of the submersible and the isokinetic constant linear pitching motion water motion. ANSYS software is used to perform numerical calculations to investigate the changes of drag and Lifting force with velocity under different navigation states. Conclusion: In the process of surfacing, the change trend of Lifting force and drag is the same: when adjusting the navigation deflection angle, it increases rapidly, and then when floating in a constant straight line, it gradually decreases, and finally, the decrease rate tends to level off; when the elevation angle increases, the change amplitude of drag and Lifting force increases. During the dive, the drag force decreases and the Lifting force increases, gradually, the rate of decrease of drag force and the rate of increase of Lifting force become smaller; when the pitch angle increases, the Lifting force decreases rapidly and the decrease of drag force becomes larger.
Research on multi-condition and multi-objective control of pumped storage unit optimized by improved multi-objective particle swarm optimization algorithm
Authors: Jiang Xiaoping , Xiu Tianning , Yu Hao
Published: June 2024

In order to maintain good control quality of the pumped storage unit regulation system during the switching of operating conditions, a multi-objective optimization framework based on improved multi-objective particle swarm optimization algorithm is proposed, which takes into account the control stability, rapidity and robustness under multiple working conditions. Firstly, the fractional order PID controller with higher applicability and flexibility is introduced to replace the traditional PID controller. Then, an objective function considering the ITAE index of low-head and medium-high-head conditions is constructed. On this basis, the multi-objective particle swarm optimization algorithm with pigeon swarm search operator, adaptive Cauchy mutation strategy and improved initialization method is used to optimize the controller parameters, and the multi-condition and multi-objective fractional order PID optimal control of pumped storage unit regulation system is realized. Through simulation, it is proved that the controller parameters based on the framework optimization proposed in this paper have strong adaptability and robustness under different working conditions, which provides a new idea for the optimal control of pumped storage unit regulation system.
Numerical investigation of the hydrodynamic properties of oscillating water column air chambers
Authors: Ding JiaWei , Chen Zhenmu , Zhu Baoshan , Xuan Dongji , Shen Yunde , Li Yong , Wu Mingge
Published: June 2024

The oceans occupy nearly 71% of the Earth’s surface area. The ocean is rich in energy, and wave energy is one of its important components. Therefore, the study of wave energy generation devices is an important issue. In this paper, we analyze the effect of the size of the air chamber structure on the OWC (oscillating water column) wave energy conversion device under the action of unidirectional regular waves. To analyze the performance of the OWC device under real sea conditions, the wave climate at Sanmenxia is used as the experimental parameter. The performance and characteristic response with the variation of incident wave height, air chamber width and front wall thickness, are analyzed. The results show that the incident wave height, air chamber width, and front wall draft have significant effects on the performance of OWC. With the increase of incident wave height, the wave nonlinear effect increases. As the air chamber width decreases, the horizontal surface inside the air chamber undulates smoothly and the standing wave phenomenon disappears.
POD mode analysis of the wake flow of Savonius hydrokinetic turbine runner
Authors: Guang Weilong , Pan Jiale , Liu Qiang , Lu Jiahao , Tao Ran , Zhu Di , Xiao Ruofu
Published: June 2024

The Savonius hydrokinetic turbine can be applied to ocean currents to improve the utilization of ocean current energy. To deeply understand the intrinsic correlation of wake flow field, this article analyzes the wake of the Savonius hydrokinetic turbine by combining proper orthogonal decomposition(POD). The results represent that the proper orthogonal decomposition can reconstruct the original wake velocity flow field to a high extent, accurately extract the main flow characteristics in the wake of the Savonius turbine, and effectively remove the flow field noise signal. In the wake of the Savonius turbine, there is a correlation between the high-order modes and the low-order modes extracted by the POD method. The decomposed flow field laws will support data-driven research in the future.
Analysis of calculation conditions for transition process of pumped storage power station
Authors: Ren Taozhe , Cheng Yanan , Wang Jue , Zhao Long
Published: June 2024

The calculation of transition process of pumped storage power station needs to consider many complicated working conditions. By studying the transition process calculation conditions of industry regulations and actual power stations, this paper analyzes the parameters that affect the transition process calculation, comprehensively considers the safety and economic benefits of power stations to determine the main calculation conditions, and puts forward the conditions that should be paid attention to in the transition process calculation of pumped storage power stations, so as to provide references for the selection of transition process calculation conditions of relevant power stations.
Hydraulic transient calculation by wave tracking method for pumped storage power plant with four units in a diversion system
Authors: Yin Xinyue , Zeng Zongyao , Wang Yuchuan , Chen Hongyu , Ma Dong
Published: June 2024

Hydraulic transient calculations are a key issue related to the operational safety of pumped storage power plants. Based on the new calculation method, wave tracking method, this paper establishes a calculation model for the hydraulic transient of pumped storage power plant, verifies the accuracy of the calculation model through hydraulic model experiments, and calculates the transient process of Guangdong Qingyuan pumped storage power plant. The results show that the calculation error is reduced by considering the difference of wave velocity of different branch pipes by wave tracking method. The wave tracking method is convenient to establish a calculation model of pumped storage power plant with four units in a diversion system, which is suitable for the load shedding transient regime of the turbine mode and the pump outage condition, and the accuracy is good. Wave parameters visually show the connection between flow rate, pressure changes within the water transmission system, and surge fluctuations in the regulator well throughout the hydraulic transition.
Study of Hydrofoil Unstable Partial Cavitation Emphasizing Unstable Sheet Cavitation Phenomenon
Authors: Wang Lin , Tang Fangping
Published: June 2024

Unstable partial cavitation phenomenon often occurs during the operation of axial flow pumps. In this paper, the hydrofoil of an axial flow pump is taken as the research object, and the cavitation morphology at the design angle of attack is obtained by high-speed photography. And the flow characteristics under the transformation cavitation number of sheet cloud cavitation are studied by SBES turbulence model. The hydrofoil has hydrodynamic phenomena such as unstable sheet cavitation and multistage cloud cavitation. The high pressure propagating upstream from the trailing edge may be the cause of secondary cloud shedding, and the closer to the hydrofoil wall surface, the greater the intensity of this pressure. The frequency of unstable sheet cavitation shedding is 166.6 Hz. The instable closure of cavitation and the hydrofoil wall may be the main cause of unstable sheet cavitation formation. The generated quasi-periodic re-entrant jet will have a greater impact on the flow in the rear of the hydrofoil. This study provides reference for the design and operation of axial flow pumps and prevention of cavitation damage.
Numerical simulation on unsteady cavitating flows in a rotational hydrodynamic cavitation reactor
Authors: Meng G Q Q G , Zhou W J , Jia Y F
Published: June 2024

The RNG k-ε turbulence model and mass transport cavitation model Zwart-Gerber-Belamri are used to simulate unsteady cavitating flows in a rotational hydrodynamic cavitation reactor (RHCR). The RHCR is mainly composed of rotor and stator. Unsteady cavitation flow field analyses in RHCR are focused mainly near the rotor surface. The numerical simulation results are in good agreement with the experimental data. The frequency of pressure fluctuations and streamline distribution are discussed by setting 10 monitoring points near the rotor surface. The numerical simulation results shows that the main frequency of pressure fluctuation inside RHCR is 24f
r and 72f
r; the maximum amplitude of pressure fluctuations appears near the inlet, and its value about 3 times than the minimum. Moreover, the streamline distribution analyses demonstrate that the vortex appears near the rotor surface, and is generating, growth and disappearing with time. The shape, vortex center and intensity of the vortex near the inlet change drastically with time. This research provided a reference for the optimization design of RHCR.
Degradation of tetracycline by combining hydrodynamic cavitation (HC) and persulfates (PS)
Authors: Zhu Xiufeng , Xuan Xiaoxu , Manickam Sivakumar , Yoon Joon Yong , Wang Jingying , Sun Xun
Published: June 2024

The ecological and human health risks caused by the overuse of antibiotics have aroused widespread concern. Due to the characteristics of antibiotics themselves, they cannot be effectively removed by traditional treatment methods. HC is considered as a new and innovative chemical process enhancement technique. which exhibits remarkable efficiency in degrading stubborn organic pollutants, and can effectively cooperate with various physical and chemical methods. In this study, the hydrodynamic cavitation (HC) technology was used to activate peroxymonosulfate (PMS) and peroxodisulfate (PDS) to produce strong oxidizing active substances (SO4
-•) to degrade tetracycline (TC) wastewater with an initial concentration of 30 mg/L. The results show that a positive relationship between the degradation efficiency of TC and both the inlet pressure as well as the dose of PS applied. HC can enable full activation of PMS and PS, the max synergistic index of HC-PMS and HC-PDS was 1.72 and 24.81, respectively. Therefore, the HC-PS system can provide a novel technical route for the treatment of antibiotic wastewater.
Degradation of tetracycline by combining hydrodynamic cavitation (HC) and ultraviolet (UV)
Authors: Liu Shuai , Xuan Xiaoxu , Manickam Sivakumar , Yoon Joon Yong , Leung Dennis YC , Sun Xun
Published: June 2024

Antibiotics have become a new type of organic pollutant. Traditional methods of antibiotic treatment have several problems, including low treatment efficiency, high cost, and low safety. As an emerging process intensification technology, hydrodynamic cavitation (HC) can significantly enhance degradation efficiency coupling with other treatment means. This work studies the degradation effect of a representative antibiotic, tetracycline, by combining HC and UV. The effect of various operating factors, including inlet pressure, initial concentration, pH, and temperature, is analyzed. It is found that HC/UV can obtain 1.7∼4.2 times more effectiveness than that of sole use of HC or UV.
Experimental and numerical studies on the partial cavitation in a Venturi
Authors: You Weibin , Xuan Xiaoxu , Chen Songying , Yoon Joon Yong , Sun Xun
Published: June 2024

To effectively control the adverse effects of cavitation, it is crucial to understand the mechanism behind the formation of cloud cavitation. The transition from sheet to cloud cavitation, or cavitation shedding, can be caused by two mechanisms: re-entrant jet and condensation shock. This study investigated the shedding mechanism of partial cavitation in a Venturi using high-speed photography and Large-Eddy Simulation. The Rankine-Hugoniot equation was used to verify that the cavitation shedding mechanism: the condensation shock at σ = 0.37 and the re-entrant jet mechanism at σ = 0.98. Both operating conditions exhibit backflow, which can cause variations in image grayscale values. The relation between backflowing velocity and grayscale variation was identified in different shedding mechanisms. When the adverse pressure gradient is constant, the shock velocity is inversely proportional to the image grayscale variation, while the re-entrant jet velocity is proportional to it. These findings may contribute to a better understanding of cavitation shedding mechanism.
Effects of cavitation on the vortex shedding behind a truncated hydrofoil subjected to forced oscillation
Authors: Chen Jian , Escaler Xavier
Published: June 2024

Cavitating vortex shedding behind a truncated NACA 0009 hydrofoil subjected to forced oscillation has been numerically investigated using a one degree-of-freedom (1 DOF) model coupled with a homogeneous mixture cavitation model. The pitching motion of the hydrofoil has been prescribed using a sinusoidal function with a fixed amplitude and variable frequencies ranging from lock-off values below the vortex shedding frequency to values well above it and passing through the lock-in condition. The obtained results have permitted us to study the change in the dynamics and morphology of the shed-vortex structures with varying hydrofoil oscillation frequencies when cavitation takes place. More specifically, it has been found that the frequency regime of the lock-in condition is altered due to the occurrence and development of cavitation. Also, two distinct wake patterns have been observed for oscillating frequencies below and above the vortex shedding frequency. Furthermore, the phase angle between the applied torque and the hydrofoil surface acceleration has been estimated as a function of the excitation frequency and the cavitation number, which has helped to understand the effects of cavitation on the dynamic behaviour of the shed vortices.
Study on acoustic characteristics of bubble interaction
Authors: Qi H Y , Sun X Y , Liu J T
Published: June 2024

Bubble flow exists widely in various hydraulic systems. The shape and size of the initial bubble deformed from a nozzle/orifice have a significant effect on the dynamic characteristics of the rising processes. In the monitoring of the sound signal of the bubble flow, it is found that the bubble will produce the sound signal when it detaches and rises, and the bubble flow pattern is related to the acoustic signal. In order to better understand the physical mechanism of passive acoustic emission, the acoustic characteristics of different nozzle arrays and gas flow rates were studied. The bubble acoustic statistical characteristics are obtained by filtering. The spectrogram based on time-frequency analysis is used to count the formation of individual bubbles and also to show the transient behaviour of bubble acoustics. Synchronous analysis is applied to study the image information and acoustic signal characteristics, the corresponding relationship between the flow pattern and the acoustic texture feature is established. This will provide a reference for predicting flow patterns through acoustic signals, and is significant for improving work efficiency and detecting faults.
Study on the Influence of Protuberance Amplitude on the Performance of Vertical Axis Wind Turbines
Authors: Chang H , Li D Y , Wang H J , He Y R , Zuo Z G , Liu S H
Published: June 2024

The performance of vertical axis wind turbine (VAWT) is mainly affected by the dynamic stall process of the blade. Inspired by the anti-stall performance of the humpback whale flipper, leading edge protuberances (LEPs) are applied to 2-blade VAWT. Based on computational fluid dynamics simulation method, the effects of LEPs amplitude on VAWT performance are investigated when blade tip speed ratio is 2.19. The results show that the larger the amplitude of the LEP, the lower the average power coefficient. When the number of protuberances is 3, the average power coefficient of the VAWT with a protuberance amplitude of 6.625mm is 1.8% higher than prototype blade. Considering the impact of increasing the chord length of biomimetic blades, the average tangential force coefficient of all biomimetic VAWTs decreases. The peak section performance of the bionic blade decreases significantly while the trough section performance increases significantly. The difference between the peak section and trough section of the LEPS plays an important role in improving the performance. This study provides a reference for the application of bionic protuberances in VAWTs.
Data acquisition in a simplified turbine model for prediction of unsteady vortex phenomena
Authors: Skripkin S , Suslov D , Gorelikov E , Tsoy M , Litvinov I
Published: June 2024

The utilization of machine learning in finding decisions of engineering problems is the optimal way. This study presents a new tool that applies machine learning algorithms, to predict the frequency response of an unsteady vortex phenomenon known as the precessing vortex core (PVC) that appears in a conical draft tube behind a runner. The basic values involved in Linear Support Vector Classification model training are the two components of the time-averaged velocity profile at the cone diffuser inlet and cone angle which should be accurately measured. The paper introduces the approach to accumulating an experimental database and conducting primary analysis of the implemented regimes of swirling flow in a simplified hydraulic turbine model. It was obtained that it is necessary to clearly identify the zone of recirculation flow. The presence of this zone is a necessary, but not sufficient condition for the formation of the PVC in the flow. Injection of an axial jet in a situation with moderate swirl flow allows to shift the PVC frequency about by 10% relative to the PVC frequency without an additional jet.
Intelligent Positioning System Design for Bridge Crane in Hydropower Plant
Authors: Chen Tiehua , Xu Ming , Zou Yanze , Wu Guangxin , Zhao Xinyu , Pan Yu
Published: June 2024

The compound nested control method of PID control and fuzzy control is used to control the walking position and speed of the bridge crane, and image processing technology is applied to detect the critical position during rotor hoisting. The system simulation is carried out using Matlab/Simulink, and the feasibility of the control method is verified based on the overshoot, response time, and stability indicators with the unit step signal as the excitation. The results show that the time required to reach steady state through fixed parameter PID simulation analysis is 0.237 s, and the overshoot is 3.3%. The time required for steady state using fuzzy PID control is 0.12s, the response speed is better than that of fixed parameter PID control, and the system has no overshoot. The image of the stator captured by the camera is processed by OpenCV. Firstly, the image is grayed and the Gaussian filtering is used to remove the image noise. Then, the stator edge contour is detected based on the Canny edge detection algorithm. The test shows that OpenCV can accurately identify the edge of the stator and extract the central coordinates of the stator image, which assists the bridge crane in accurate positioning.
Optimization conversion of integrated energy system under stepped carbon trading mechanism considering source-load uncertainty
Authors: Liu Yipeng , Zhang Yeke
Published: June 2024

This paper develops an optimization strategy for integrated energy systems under a stepwise carbon trading mechanism, considering source-load uncertainty. It aims to enhance operational efficiency and reduce carbon emissions within economic and environmental constraints. The strategy examines the impact of carbon pricing on energy management and leverages uncertainty for better energy efficiency and lower emissions. A case study confirms its effectiveness in improving energy utilization and reducing carbon footprint.
Energy-saving characteristics of pneumatic conveying based on the Dune model of elbow installation with different radius of curvature
Authors: Wang Yunfei , Yan Fei
Published: June 2024

During pneumatic conveying, particles undergo rapid horizontal movement and experience significant wear and collision when changing direction at the elbow pipe due to inertia. Consequently, to minimize energy consumption in transportation, a Dune model has been developed specifically for bends with varying radii of curvature. In this paper, the pressure drops the additional pressure drop coefficient, and the energy loss coefficient of the system are studied. At the minimum pressure drop velocity, PIV is used to capture the particle velocity at different locations in the vertical pipe. The findings reveal that the Dune model installation successfully minimizes the minimum pressure drop velocity, and the maximum pressure drop velocity is reduced by 10.36%. In addition, the energy loss coefficient decreased by 11.56%. Particles in vertical pipes have greater axial velocity than particles in pipes without dunes.
Permanent magnet synchronous motor NFTSM control based on novel exponential convergence law and ESO
Authors: Ren Zhiling , Zhang Enpu
Published: June 2024

To solve the problems of slow convergence and serious system chatter in PMSM speed regulation of traditional exponential approach law sliding mode control (SMC), a PMSM fast terminal slip mode (NFTSM) beat free predictive current control (DPCC) strategy based on improved exponential control rate and extended sliding mode observer (ESO) is proposed. The non-singular fast terminal slip-mode controller based on improved exponential control rate and ESO is used in the speed loop. A new exponential approach law is proposed. The stability of the system is proved by using the Lyapunov function. The robustness of the speed controller is improved while reducing the vibration. DPCC control strategy based on ESO is adopted for the current loop to compensate comprehensive disturbance of the current loop. The experiment results show that the control strategy has good speed tracking performance and anti-jamming performance.
Analyses of non-clean surface compressor blade cascades’ aerodynamic performance deterioration
Authors: Bu Yinglei , Wang Chenliang , Wang Meng , Wang Yanhua , Ren Xin
Published: June 2024

The efficiency and dependability of the engine are directly impacted by the compressor’s performance, which is a crucial part of gas turbines. The blade cascade is significantly influenced by surface roughness in terms of flow characteristics and aerodynamic performance. In this study, the NACA65-410 airfoil is selected as the research object to investigate the variations in blade cascade performance and flow characteristics under different inflow and roughness conditions. The results show that the smooth surface blade cascade performs optimally when the Reynolds number increases from 120,000 to 200,000. As the angle of attack increases from -5° to 8°, the blade cascade performance deteriorates, and the degree of performance degradation increases with the increase in angle of attack. For the roughened blade cascade surface, the performance initially improves and then decreases as the equivalent sand grain density increases, and there exists a critical equivalent sand grain density that maximizes the blade cascade performance. When the Reynolds number is 120,000, the critical equivalent sand grain density is 225 μm, and when the Reynolds number is 160,000, the critical equivalent sand grain density is 111 μm. Based on the findings of this study, the degradation pattern of blade cascade performance can be predicted, and it can be utilized to enhance the overall performance of the compressor.
Preliminary design and optimization of heat transfer element for calorimeter in neutral beam injection system
Authors: Pan Zhuo , Xie Yuanlai , Tang Ning
Published: June 2024

The calorimeter is the primary high heat flux component of the neutral beam injection (NBI) system. To meet the requirements of China’s future high-power and long-pulse NBI system for efficient heat removal from the calorimeter, this study proposes a preliminary design for a calorimeter heat transfer element (HTE) mainly formed by vacuum brazing the front plate and back plate, featuring internal hypervapotron channels to enhance heat transfer. Parametric design and numerical simulations are applied to find the optimal channel parameters, including channel height (h), fillet radius (r), and slot width (s). Response surface analysis is used to process the results of the design schemes. The thermohydraulic performance of the optimized design under different channel flow velocities and heat flux densities is further analyzed. The results indicate that the optimal parameters are as follows: h=5 mm, r=1 mm, and s=1.5 mm. The h and s mainly influence HTE’s maximum temperature and pressure drop per unit length, respectively. The optimized design can meet the design criteria with a normal channel flow velocity of 10 m/s. To prevent the HTE pressure drop from surpassing 2 MPa, the channel flow velocity should not exceed 12 m/s. The design and optimization results of this study can serve as guidance for the engineering design of the calorimeter in China’s future NBI system.
Torque balance control of underwater dual-motor system
Authors: Liu Yuqi , Huang Yuanfeng , Xiong Bin , Bian Hui
Published: June 2024

The duocentric motor drive system is commonly employed in various fields such as the printing and dyeing paper industry and industrial production. As one of the dual-motor systems, the duocentric motor system sometimes causes torque imbalance due to sudden load changes during underwater operation. This imbalance seriously affects the coordinated operation of the duocentric motor system. Addressing these issues, this paper proposes a control approach utilizing a combination of speed and torque control to manage the duocentric motor system. Through simulation, this control technique is validated to enhance the operation capability of the duocentric motor while ensuring system stability and reliability.
The lithium battery state of charge estimation based on the fractional order unscented kalman filter algorithm
Authors: Jie Junzheng , Gao Yu , Liu Wenhui
Published: June 2024

In the assessment of the state of charge (SOC) of lithium batteries, it has been observed that the conventional integer-order second-order resistance-capacitance (RC) network falls short in accurately replicating the non-linear attributes and the precision of SOC estimation influenced by the internal polarization reaction within the battery. Thus, we present the incorporation of constant-phase element (CPE) and Warburg components to achieve a model with superior recognition accuracy compared to the conventional second-order equivalent circuit model(ECM). The parameterization is carried out using the particle swarm optimization algorithm, resulting in enhanced robustness of parameter identification. Later on, when we mixed the regular Unscented Kalman Filter (UKF) algorithm with the fractional-order model (FOM), we obtained an algorithm to estimate the SOC of lithium battery in real time, named FOUKF, and compared FOUKF with the integer-order Extended Kalman Filter (EKF) and UKF algorithms. This confirms that the model is reliable and the algorithm’s estimation is accurate.
A generation expansion planning method considering conditional value-at-risk
Authors: Li Bicheng , Zhou Renjun , He Qianshuai , Li Hongchang
Published: June 2024

The uncertainty of load forecasting can lead to certain risks in generation expansion planning. Different from the traditional large-capacity unit planning in the past, renewable energy has the characteristics of small single-machine capacity and fast construction speed, etc. The uncertainty of load forecasting will have a more significant impact on the results of generation expansion planning including renewable energy. For this reason, this paper proposes a generation expansion planning idea considering load forecast uncertainty based on conditional value-at-risk (CVaR). Firstly, scenario technology is used to simulate the uncertainty, and CVaR is introduced to quantify the risk of generation expansion planning. Then, considering the coordinated development of traditional and renewable energy sources, a generation expansion planning model that considers risk is established to minimize the total costs. Finally, the effectiveness of the model was verified through a case study, and this model has reference significance for balancing the economy and reliability in generation expansion planning.
Comprehensive performance analysis of CST-PV system based on spectral beam splitting film
Authors: Wang Linhao , Zhang Xin , Lei Dongqiang , Lv Yue , Guo Ruishen , Wang Zhifeng
Published: June 2024

In this paper, a novel linear Fresnel concentrator (LFC) with a rotating platform was constructed, and a novel concentrated solar thermal and photovoltaic (CST-PV) hybrid system utilizing spectral beam splitting was established on the LFC. A spectral beam-splitting film (SBSF) was coated on the PV cell’s inner glass wall, replacing the LFC’s primary reflector. The SBSF can transmit the solar spectrum of 300-1100 nm to the photovoltaic (PV) cells and reflect the remaining solar wavelengths to the absorber to generate heat. The LFC’s cosine efficiency and end efficiency after azimuthal compensation by a rotating platform were calculated through theoretical analysis. The effects of temperature on the efficiency of PV and linear Fresnel solar systems were studied through experimental and numerical simulations. The comprehensive utilization efficiency evaluation method was established. The results show that the LFC’s end efficiency and cosine efficiency in this paper, after azimuthal compensation, increased by 31.7% and 33.7%, respectively, compared with the east-west and north-south axis placement. The comprehensive utilization efficiency of the CST-PV system based on SBS is 61.58%, which increased by 13.47% compared to that of the single fixed PV system.
A modeling method for the control circuit of a double-fed induction generator in a wind power system based on multimodel fusion
Authors: Zhang Wei , Li Qiangliu
Published: June 2024

The current modeling techniques of a Double-fed induction generator (DFIG) for wind power systems have shortcomings in the idealization of equipment internal parameters and unitization of system coupling. In this paper, a multi-model fusion method of doubly-fed induction wind turbine modeling for wind power systems is proposed. Firstly, the 1.5 MW DFIG body is constructed according to the parameters of the physical prototype. Then, to realize the system’s control of DFIG, the DIFG external circuit and control circuit of the wind power system are built to realize multi-system coupling simulation modeling. Through simulation analysis, the effectiveness of the multi-model coupling simulation system and the availability of the method are proved.
A double axis synchronous control method for plunger pump based on fuzzy control
Authors: Wei Xingya , Qi Jialin , Zeng Ting , Yin Shen , Liu Jianze
Published: June 2024

A fuzzy control method is proposed to address the problem of asynchronous motor position caused by uncertain factors, such as changes in motor load parameters and external disturbances in piston pumps driven by servo motors. We simulate three typical inputs and random load disturbances of dual-axis motor position synchronization using SIMULINK and apply this control strategy to high-precision piston pumps. The simulation and experimental results show that using the fuzzy control method can make the synchronous position tracking accuracy of the dual-axis motor better than 0.2%, and the synchronization error converges to zero after load disturbance. This method has certain anti-interference abilities.