bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inversion Calculation and Analysis of Transient Process for Pumped Storage Power Station
Authors: Ma Yanmei , Zhang Hong , Fan Jiayi , Zhang Jian 
Published: June 2024

Abstract
In order to more accurately evaluate the transition process characteristics of pump turbine in pumped storage power station, this paper summarized a systematic inversion calculation and analysis method. Using this inversion calculation method, this paper calculated and analyzed the pressure changes for different load conditions of the same unit, similar conditions of other units in the same hydraulic unit and similar conditions of similar units in other hydraulic units based on the actual measured data of load rejecting test in a pumped storage power station. The inversion calculation results are in good agreement with the experimental measured data, which proves that it is feasible to predict the transient pressure by using this method for inversion calculation.
Effect of guide vane closing speed deviation on transition process in pumped storage power plant
Authors: Li Dongkuo , Zhang Fei , Ni Jinbing , Zhao Yifeng , Gui Zhonghua , Ding Jinghuan , Han Wenfu 
Published: June 2024

Abstract
The guide vane closing law is a crucial role in ensuring the hydraulic transients of pumped storage power plant. It is also essential for ensuring the safe operation of pumped storage power plant after long-term operation. Variations in the closing speed between simulated guide vane closing laws and on-site closing laws have been observed. This study first verifies the accuracy of the simulation model through load rejection tests conducted on two units. It then simulates the deviation in guide vane closing speed for these units. The deviation in guide vane closing speed does not impact the regulatory requirements for a single unit. However, variations in the closing speed between simulated guide vane closing laws and on-site closing laws have been observed. This study first verifies the accuracy of the simulation model through load rejection tests conducted on two units. It then simulates the deviation in guide vane closing speed for these units and proposes a reference range. The deviation in guide vane closing speed does not impact the regulatory requirements for a single unit. However, for two units in one pipe, opposite deviations in guide vane closing speed can result in key parameters failing to meet regulatory requirements.
The influence of the S shaped characteristics of high head pump-turbine on the minimum pressure of draft tube
Authors: Zhang Meiqin , Su Yanyi , Chen Jianfu , Zhang Shubang , Wang Wei , Wei Xianzhu 
Published: June 2024

Abstract
The S shaped characteristics of pump-turbines have an important impact on the minimum pressure of draft tube. The quality of the S shaped characteristics is one of the key indicators to determine the success of model runner development, and this indicator is particularly important for ultra-high head pump-turbines. In order to delve deeper into the inherent relationship between the S-shaped characteristics of the runner and the optimization design and minimum pressure of draft tube, this article first defines a method for fixed-point quantitative analysis of the S shaped characteristic curve. Then, different experimental characteristic curves obtained from multiple optimized designs of the runner are used to calculate the hydraulic transition process. At the same time, the S shaped curve is quantitatively analyzed, and the relationship between the three is explored through continuous analysis. The results show that the bending degree of the equal opening lines in the middle at the S shape characteristics curves has the greatest influence on the minimum pressure at the draft tube inlet. The greater the ratio of unit flow difference to unit speed difference in the S shape characteristics curves of the equal opening line, the greater the runaway unit flow on the same equal opening line, the more favorable it is to increase the minimum pressure at the inlet of the draft tube. The optimal design of blade type and guide vane airfoil can improve the minimum pressure value of draft tube to a certain extent. The conclusions obtained in this paper can be used for reference in the research and development design of high head pump-turbine runner and the optimization calculation of transition.
Spatial distribution of rigid vorticity in pump-turbine under turbine mode with different guide vane openings
Authors: Yan X T , Kan K , Zheng Y , Chen H X 
Published: June 2024

Abstract
Under non-design operating conditions, pump-turbines often exhibit notable instabilities within their runner regions. This study endeavors to investigate the spatial distribution patterns of vortex structures occurring between runner blade channels, focusing on different guide vane opening conditions in the turbine mode of a model pump-turbine. Based on rigid vorticity vectors, the large-scale vortex structures in the channels were analysed. Additionally, this study proposes a novel approach that utilizes the relative streamline coordinates of the blade skeleton to conduct flow analysis. This method offers a quantitative description of the spatial distribution of rigid vortices and associated physical quantities within the blade channels along the streamwise, circumferential, and spanwise directions. Finally, the causes of rigid vortices were analysed. The paper presents a pioneering and advanced theoretical tool and research methodology, serving as a valuable resource for the analysis and understanding of unstable flow structures within pump-turbines.
Study on the influence of pressure-balance pipe diameter on the volumetric efficiency of pump turbine
Authors: Lv Yue , Zhou Lingjiu 
Published: June 2024

Abstract
Hydraulic machinery experiences volume loss due to flow leakage from the clearance between rotating parts and the shell. For pump turbines, fluid leakage from high-pressure to low-pressure areas through the clearance between the upper crown and lower band sealing parts causes volume loss and reduces hydraulic efficiency. The pressure-balance pipe is crucial for balancing axial hydraulic thrust, and its starting end typically lies on the inner side of the upper crown clearance. In this study, we analyze a pump turbine with three flow rates (0.9Q, 0.75Q, and 0.5Q) to illustrate the impact of clearance flow on volumetric efficiency. We consider the effect of varying pressure-balance pipe diameters on volumetric efficiency and analyze the influence of diameter changes on clearance flow. Our findings indicate that changing pressure-balance pipe diameter affects volumetric efficiency and pressure distribution in the upper clearance, with different mechanisms for high and low flow conditions. This study has important implications for pressure-balance pipe design. While ensuring that axial hydraulic thrust balancing is maintained, resizing the pressure-balance pipe diameter can improve unit operation efficiency.
The method for identifying the potential of the fast response capability of a variable-speed pumped storage turbine in pump mode
Authors: Meng L , Zheng Y , Wang X , Zhang C Y , Tian Y J , He L 
Published: June 2024

Abstract
Variable-speed pumped storage technology was being increasingly adopted by new power system to improve the operating and regulating characteristics of the hydropower unit and to stabilize the grid fluctuations. By connecting to a frequency converter, the variable-speed pumped storage unit can respond to grid fluctuations at a speed of hundreds of milliseconds. The fast response capability of a variable-speed pumped storage turbine should be considered in the design stage, be identified during the model test and be used as prerequisite during the commissioning stage of the unit. This article described the method for identifying the fast response capability and methods for improving the power regulation potential of a variable-speed pumped turbine in pump mode. The pipeline hydraulic loss, the guide vanes opening, the energy, cavitation and hump characteristics of the pump are the key parameters and should be carefully considered during the selection of the variable-speed operating zone.
Model experimental study on special frequency of hydraulic pump working condition headcover for ultra-high head pump-turbine
Authors: Lin F Z , Wang X L , Guan Z W , Hu J Y , Wang Z N , Liang Q W 
Published: June 2024

Abstract
With the accelerated construction of pumped-storage power stations, high-head and high-capacity pumped-storage units are gradually becoming the mainstream of development. When operated on-site, the high-head and high-capacity pumped-storage units reflect the phenomenon of special frequency of the head cover vibration of the water pump, which has attracted widespread attention from the industry. In order to deeply reveal the flow mechanism of pumped-storage units, model experiments on the head cover were conducted through the similarity conversion principle between the model and the prototype. The experiment results show that the occurrence of specific frequency in the Head cover of the water pump during operation is due to the rotating flow separation in the vaneless area.
A Field Test Study on the Instability of a Pump-Turbine under Turbine Mode
Authors: Song X H , Xia M , Hu H P , Zhao W Q , Wang Z W 
Published: June 2024

Abstract
In the context of increasing demand for flexible operation of hydropower plants, this study analyses the factors leading to instability in a prototype pump turbine under turbine mode, based on experimental data collected on-site. Pressure sensors and accelerometers were installed to compare pressure signals and vibration acceleration signals. The test results show that the characteristics of pressure fluctuation are dominated by three specific factors under different output power. Vibration reaches its maximum value at approximately 30% of the rated output and its minimum value at around 70% of the rated output, and the causes of twice increases in vibration is not the same. These characteristics often indicate potential unsteady flow, vortex-induced vibration, and flow separation, subsequently affecting the stability of the pump turbine. Understanding the conditions and severity of the occurrence of instability characteristics in the unit is of great significance for power plant personnel to adjust the unit’s operation strategy and improve operational efficiency.
Study on the influence of guide vane - blade number matching relationship (20-9) on the phase resonance risk coefficient of pumped storage units
Authors: Zhang Tao , Li Jinwei , Yang Weibin , Liu Yanyan 
Published: June 2024

Abstract
In this paper, 19 pumped storage units put into operation or under construction in China (the matching relationship between the number of guide vanes and blades is 20-9, and the rated output of a single unit is not less than 200MW) were taken as the research object. Considering the risk of phase resonance caused by pressure wave propagation in the spiral casing of the unit, the phase resonance risk coefficients of units with different rotational speeds were analyzed. The concept of perimeter equivalent coefficient was proposed, and the design criteria for controlling the phase resonance risk coefficient within 25% was obtained, which provided references for optimal hydraulic design of pumped storage units.
Numerical analysis of the transient characteristics of internal flow in the acceleration process of variable speed regulation of a centrifugal pump
Authors: Zhang Haichen , Sun Jian , Dong Wei , Dong Yan , Li Peixuan 
Published: June 2024

Abstract
In this study, a method of combining Flowmaster and ANSYS CFX software was adopted. Based on the consistency between the numerical calculation results of the hydraulic performance of a centrifugal pump and the test results, an operating model of a centrifugal pump system is established, variation law of the external characteristic parameters in the transient process is obtained, and different acceleration times and modes are set. The change law of the transient external characteristics and the evolution mechanism of the internal flow field during the variable speed regulation and acceleration of the centrifugal pump are disclosed. By introducing a control system evaluation index, the effects of acceleration time and mode on performance and internal flow field of variable speed control process of the centrifugal pump are analysed in detail. The results show that the turbulent kinetic energy in the pump changes violently, and the high turbulent kinetic energy and high vorticity are widely distributed, which has an obvious transient effect. An exponential acceleration method can effectively reduce the peak value and overshoot of external characteristic parameters while reducing the speed regulation time.
Performance prediction of IS centrifugal pump based on improved BP neural network
Authors: Yu D H , Chen Y , Wang C , Yang Y C , Ma L L , Ma W S 
Published: June 2024

Abstract
The improved BP neural network was applied to establish prediction models for rated flow and rated head separately, the neural network structures were 8-11-1 and 5-6-1 respectively. 123 sets of pump experimental data were organized as training samples, and the other 15 sets of data were used as test samples. The results show that the training of the two networks converges quickly, the predictive values of the two performance parameters have good consistency with the experimental values, and the average testing errors of rated flow and rated head are 4.2% and 4.7%, respectively. The neural network prediction models established are accurate and effective, meeting the requirements of engineering applications.
Study on the form of sealing ring and its sealing characteristics of centrifugal pump
Authors: Yan Na , Wang Xiaohang , Wu Xidong , Zhu Jiwen 
Published: June 2024

Abstract
The sealing ring, also known as the leakage relief ring, is usually composed of a fixed part and a rotating part, which is used to reduce the gap leakage between the rotating part of the pump and the fixed part, and its structural form and clearance value have a great impact on the stability and efficiency of the pump set. In this paper, the sealing ring between the top cover impeller of a centrifugal pump is used as the research object, and the empirical analysis method and numerical simulation method are used to analyse the water sealing characteristics of the sealing ring structure commonly used in five projects from the aspects of leakage amount and energy consumption, and compare. The results show that the labyrinth, stepped and comb tooth sealing rings have good water sealing effect. Aiming at the matching of different sealing gaps and diffusion domains of stepped sealing rings, the influence of sealing structure size on water sealing characteristics was explored, which provided a technical basis for the selection of sealing ring structure and the determination of matching size of centrifugal pump.
Study of the Effect of Incoming Flow with Fluctuating Gas Void Fraction on Transient Characteristics of a Three-stage Multiphase Pump
Authors: Tan Zheng , Zhang Jinya , Zhou Wenbo , Zhang Yongxue 
Published: June 2024

Abstract
For the oil field with high gas content, the oil well produced has obvious gas content fluctuation characteristics. The unsteady flow of multiphase pump will be caused by the fluctuation flow into the pump. In this paper, the unsteady numerical simulation of the flow field in a three-stage multiphase pump is carried out by using Euler-Euler two-fluid model and SST turbulence model. The results show that the pressurization and torque of each impeller change with the fluctuation of the inlet gas content. The second stage impeller has the highest fluctuation due to the change of flow pattern. The inlet gas rate pulsation frequency and static and static interference have significant effects on the pressure pulsation in the impeller, and the dominant frequency is gas rate pulsation frequency or 11 times rotation frequency. The dominant frequency of the diffuser is the blade passing frequency and its double frequency, and the pulsation frequency of the gas content is the secondary frequency and the amplitude is relatively stable. The axial force increases with the increase of gas content, while the radial force changes in reverse.
Investigation on flow structure and pressure fluctuation of gas-liquid two-phase flow in a mixed flow pump
Authors: Han Yadong , Wu Guoying , Lin Yuanhang , Tan Lei 
Published: June 2024

Abstract
Mixed flow pump is characterized by high-efficiency operation and wide range of flow rate conditions, while research on transporting gas-liquid two-phase flow is quite limited. The present work investigates the energy performance, two-phase flow pattern and pressure fluctuations of a mixed flow pump, on basis of the numerical method of inhomogeneous Eulerian-Eulerian multiphase flow model. Results show that the pump head and efficiency decline with the increase of gas volume fraction. In impeller, gas phase is mainly distributed at the tip clearance, the blade pressure side and suction side, and the hub outlet. The low pressure of tip leakage vortex core leads to the gas phase concentration and the formation of gas strip. Moreover, X-shaped gas strip appears at high gas volume fraction (GVF). In guide vane, gas phase is mainly distributed at the leading edge of blade pressure side, the blade suction side, and the middle of passage. As the inlet GVF increases, the spatial-temporal evolution of the gas phase shows obvious differences. The strong gas-liquid interaction causes broad low-frequency fluctuations, and the rotor-stator interference causes significant blade passing frequencies in the mixed flow pump.
Research progress on hydraulic performance prediction method for large dredge pumps
Authors: Cao Lei , Guo Tao , Zhuang Haifei , Hu Jingzhao 
Published: June 2024

Abstract
The dredge pump is the core equipment in a dredger, which is used to transport dense dredged soil excavated by the dredger. However, the slurry performance of a dredge pump is usually calculated via empirical formula based on the clean-water performance data obtained by numerical simulation or model test, and the conversion accuracy is difficult to evaluate. This paper focuses on reviewing the present technologies of slurry performance test as well as numerical simulation for centrifugal solid-liquid pump. Research progress on special instruments required for testing slurry parameters as well as numerical models for simulating dense solid-liquid flows was summarized. An example was presented to illustrate the scale effect and possible error source in performance conversion between model and prototype pump and then technical difficulties and future research directions in hydraulic performance prediction for dredge pump were put forward.
Structural improvement of a dredge pump based on numerical analysis to prolong its service life
Authors: Hu J , Cao L , Guo T , Zhu Z , Wu Y 
Published: June 2024

Abstract
Dredge pumps are prone to irreparable damage during offshore constructions: the flow passage components are rapidly worn out, and pump shafts often break. It seriously affects the construction efficiency and progress. For the case of high concentration conveying of medium coarse sand, the flow in a dredge pump was numerically studied to analyze the flow force on the impeller and the trajectories of sand particles in the impeller. A discrete phase model was introduced to predict the wear on the impeller, and the life of the pump shaft was predicted using S-N curves and the Rain-flow counting method. A new blade profile and an endwall profile were proposed to use to reduce the wear on the impeller and the structure of the shaft head were optimized to reduce the stress concentration coefficient. The numerical results showed that these measures can significantly improve the service life of the pump.
Analysis of axial force pulsation in a high-pressure decoking pump
Authors: Lin Yanpi , Xu Shengjun , Chen Zhandong , Wei Zhicong , Li Xiaojun , Zhu Zhuchao 
Published: June 2024

Abstract
The high-pressure decoking pump of delayed coking plants in the petrochemical field is a horizontal multistage centrifugal pump. The axial force of the decoking pump is immense, and it needs to start intermittently in the delayed coking process, which will cause axial instability. Through the time domain and frequency domain analysis of the axial force fluctuation signal, the magnitude and stability of the decoking pump axial force under different flow rate and rotational speed conditions are examined in this study. And by introducing the definition of the pressure pulsation intensity coefficient (PPIC) and the Pearson correlation coefficient (PCCs), the correlation of axial force stability and pressure signal pulsation intensity is analyzed. The research can help to establish the rotor axial force instability evaluation system of multistage pump rotor and provide some guidance for the rotor design of the centrifugal pump.
Optimization and Improvement of Three-phase Asynchronous Motor Soft Starter Control Circuit
Authors: Jin Y , Dong J J , Yang X W 
Published: June 2024

Abstract
The soft starters of ABB company are used in a pumped storage power station. Sometimes, a phase absent fault was reported during the process of the motor starting and then led to starting failure. To solve this problem, this article first explained the working principle of the device, and then analyzed the design of the control circuit and the characteristics of the components. Combined with the actual inspection results to find the crux of the problem, It proposed optimization and improvement methods for the soft starter control circuit, and achieved the desired results.
Research on hydraulic characteristics’ sensitivity analysis of the hydraulic inclined shaft turning
Authors: Xuan Zhang , Jie Wei , Han Wu , Lu Zhao 
Published: June 2024

Abstract
The parameters of the hydraulic inclined shaft turning directly affects the flow field characteristics in the bending section and the construction difficulty of the bending section. Three-dimensional computational fluid dynamics (CFD) numerical simulation method was used to systematically study the hydraulic characteristics under different flow velocities, turning radii and turning angles. The results indicate that the flow velocities and the size of the turning radius have little influence on the flow velocity distribution in the bending section. The larger the turning angle, the larger the fast flow velocity area in the bending section. But the extreme values of fast flow velocity remain basically unchanged, and the length required for adjusting the flow velocity distribution after the curved section becomes longer. The faster the flow velocity, the smaller the turning radius, and the larger the turning angle, the greater the centrifugal force generated and the more pronounced the difference in pressure distribution between the inside and outside of the bend section. The head loss in the bending section is consistent with the empirical formula in the specifications. As the radius of curvature gradually increases from 1D to 3D, the head loss (primarily due to local head loss) decreases gradually. When the radius of the bending section continues to increase, the reduction in local head loss becomes less significant, but the increase in frictional head loss leads to a slight overall increase in head loss.