Study of flow characteristics in the S-shaped region of a pump-turbine at Baoquan pumped storage power station

2015 ◽  
Vol 10 (2) ◽  
pp. 242-249
Author(s):  
Jun Li ◽  
Yongmei Cao ◽  
Lei Wang ◽  
Xiaochong Chen
Keyword(s):  
Cfd Simulation ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Modern Society ◽  
Stable Operation ◽  
Power Station ◽  
Pump Turbine ◽  
Research Findings ◽  
Computational Fluid Dynamics Cfd ◽  
Pumped Storage

Pumped storage power plays increasingly important roles in modern society but requires some complex equipment. The characteristics of the S-shaped region of a reversible pump-turbine caused significant difficulties in the stable operation of the unit. In this paper, the 1# pump-turbine at Baoquan storage power station is studied. The basic variations of the internal flow were understood using Computational Fluid Dynamics (CFD) simulation, and the relationship between head variation and the ‘S’ characteristic was analyzed. It was found that the basis of the ‘S’ characteristics was channel congestion caused by vortices. Methods that might be used to eliminate the effects of the ‘S’ characteristic are also given. The authors believe that the research findings in this paper could provide the technical support needed for stable operation of such units, as well as further studies of the ‘S’ characteristic.

scholarly journals Analysis of Rotor-Stator Interaction of a Pump-Turbine with Splitter Blades in a Pump Mode

Mathematics ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1465 ◽  
Author(s):  
Haiqin Song ◽  
Jinfeng Zhang ◽  
Ping Huang ◽  
Haikun Cai ◽  
Puyu Cao ◽  
...  
Keyword(s):  
Radial Force ◽  
Stable Operation ◽  
Power Station ◽  
Pump Turbine ◽  
Main Frequency ◽  
Pulsation Amplitude ◽  
Depth Analysis ◽  
Rotor Stator Interaction ◽  
Guide Blade ◽  
Pumped Storage

The pump-turbine is the core component of a pumped storage power station. This paper considers an in-depth analysis of the rotor-stator interaction characteristics under computational fluid dynamics (CFD) and experimental measurements of pump-turbine with splitter blades used in a domestic pumped storage power station. The results show that as the guide blade opening increases, the rotor-stator interaction of the pump-turbine intensifies and the magnitude of the runner radial force and its pulsation amplitude as well as the magnitude of the guide blade water moment and its pulsation amplitude also increase. In addition, when the opening degree increases from 9.8° to 17.5°, the influence on the main frequency is mainly reflected in the phase change. While the opening degree increases from 17.5° to 24.8°, the influence on the main frequency is mainly reflected in the amplitude change. Moreover, the amplitude of 5fn at opening 9.8° and opening 24.8° is greater than the optimal opening 17.5°, indicating that deviation from the optimal opening will aggravate the difference of rotor-stator interaction between splitter blades and guide blades. In the paper, the influence of guide blade openings on the rotor-stator interaction between the splitter guide blade is studied, which provides a theoretical reference for the stable operation of the pump-turbine.

Research on CFD Simulation of the Cement Slurry Mixer

2012 ◽  
Vol 621 ◽  
pp. 196-199
Author(s):  
Shui Ping LI ◽  
Ya Li Yuan ◽  
Lu Gang Shi
Keyword(s):  
Flow Field ◽  
High Performance ◽  
Cfd Simulation ◽  
Structural Parameters ◽  
Internal Flow ◽  
Simulation Method ◽  
Cement Slurry ◽  
Fluid Machinery ◽  
Computational Fluid Dynamics Cfd ◽  
Machinery Design

Numerical simulation method of the internal flow field of fluid machinery has become an important technology in the study of fluid machinery design. In order to obtain a high-performance cement slurry mixer, computational fluid dynamics (CFD) techniques are used to simulate the flow field in the mixer, and the simulation results are studied. According to the analysis results, the structural parameters of the mixer are modified. The results show the mixer under the revised parameters meet the design requirements well. So CFD analysis method can shorten design period and provide valuable theoretical guidance for the design of fluid machinery.

CFD Simulation of Semi-Submersible Floating Offshore Wind Turbine Under Pitch Decay Motion

2019 ◽  
Author(s):  
Yu Wang ◽  
Hamn-Ching Chen ◽  
Guilherme Vaz ◽  
Simon Burmester
Keyword(s):  
Wind Turbine ◽  
Cfd Simulation ◽  
Flow Characteristics ◽  
Hydrodynamic Pressure ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Natural Period ◽  
Hydrodynamic Damping ◽  
Computational Data ◽  
Computational Fluid Dynamics Cfd

Abstract The application of a computational fluid dynamics (CFD) code to simulate the response of a semi-submersible floating wind turbine under pitch decay motion was investigated in this study. Estimation of the natural period, the hydrodynamic damping and the flow characteristics were the main focus of this study. An extensive verification study of the simulation results was conducted to improve the confidence and reliability of the numerical simulation by the estimation of the numerical errors and uncertainties. The time series of pitch motion was plotted against model test data. In addition, the pitch period and hydrodynamic damping were calculated and compared to experimental data. Detailed flow characteristics as vorticity field and hydrodynamic pressure field on the floater surface were illustrated after post processing of the computational data. The results of the flow characteristics suggest that the heave damping plates were a major contributor to the hydrodynamic damping of this floater in pitch decay.

Study on the Relationship between Ergometer and Tensioning Force of Pre-Stressed Pier Anchor Cable

2013 ◽  
Vol 353-356 ◽  
pp. 2822-2826
Author(s):  
Jun Xing ◽  
Zhi Xin Fan
Keyword(s):  
Stable Operation ◽  
Indicator Values ◽  
Power Station ◽  
Anchor Cable ◽  
Lower Reservoir ◽  
The Difference ◽  
Pumped Storage ◽  
The Relationship

During the construction of pre-stressed anchor cables for discharging flood and sand in the lower reservoir of Pushihe Pumped-storage Power Station, the tensioning of main and secondary cables are overall carried out according to design, in which the tensioning force is divided into seventh grades, the indicator values of ergometer and tensioning force of jack were obtained by experiment, and the difference between them were compared and analysis, the results of experiment provides the basis for the long-term and stable operation of pre-stressed pier in Pushihe project.

scholarly journals Analysis of Internal Flow Characteristics of a Startup Pump Turbine at the Lowest Head under No-Load Conditions

2021 ◽  
Vol 9 (12) ◽  
pp. 1360
Author(s):  
Wei Wang ◽  
Xi Wang ◽  
Zhengwei Wang ◽  
Mabing Ni ◽  
Chunan Yang
Keyword(s):  
High Speed ◽  
Pressure Pulsation ◽  
Working Condition ◽  
Guide Vane ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Operating Conditions ◽  
Small Range ◽  
Pressure Balance ◽  
Pump Turbine

The instability of the no-load working condition of the pump turbine directly affects the grid connection of the unit, and will cause vibration and damage to the components of the unit in severe cases. In this paper, a three-dimensional full flow numerical model including the runner gap and the pressure-balance pipe was established. The method SST k-ω model was used to predict the internal flow characteristics of the pump turbine. The pressure pulsation of the runner under different operating conditions during the no-load process was compared. Because the rotation speed, flow rate, and guide vane opening of the unit change in a small range during the no-load process, the pressure pulsation characteristics of the runner are basically the same. Therefore, a working condition was selected to analyze the transient characteristics of the flow field, and it was found that there was a high-speed ring in the vaneless zone, and a stable channel vortex was generated in the runner flow passage. Analyzing the axial water thrust of each part of the runner, it was found that the axial water thrust of the runner gap was much larger than the axial water thrust of the runner blades, and it changed with time periodically. It was affected by rotor stator interaction. The main frequency was expressed as a multiple of the number of guide vanes, that is, vanes passing frequency, 22fn. During the entire no-load process, the axial water thrust of the runner changed slowly with time and fluctuated slightly.

scholarly journals Effect of Rotational Speed on Performance of Mixed Flow Pump as Turbine

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Jun Chen ◽  
Tao Dai ◽  
Qing Yang
Keyword(s):  
Energy Recovery ◽  
Theoretical Calculations ◽  
Flow Characteristics ◽  
Internal Flow ◽  
High Water ◽  
Mixed Flow ◽  
High Water Period ◽  
Shaft Power ◽  
Pumped Storage ◽  
Flow Pump

In order to research the flow characteristics of mixed flow pump as turbine (MF-PAT) with different rotation speeds, a hydraulic model of mixed flow pump was established based on a pumped storage power station. The k-ε turbulent model was used to simulate internal flow fields with three rotation speeds by SMPLEC algorithms. Subsequently, theoretical calculations and experiments were carried out to verify the precision of numerical simulation. The results showed that the rotation speed of MF-PAT has a significant impact on its performance. Both numerical calculations and experimental test presented that all efficiency curves consist of ascending and descending stages, while the shaft power and head increase nonlinearly from 1000 to 2000 r/min. When the MF-PAT  deviates from the rated environment, increase in speed is positive to the energy recovery efficiency in the high water period and negative in the dry season. This work could provide a reference for further study of MF-PAT.

scholarly journals Nonlinear Modeling of Dynamic Characteristics of Pump-Turbine

Energies ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 297
Author(s):  
Liying Wang ◽  
Kaidi Zhang ◽  
Weiguo Zhao
Keyword(s):  
Linear Model ◽  
Nonlinear Model ◽  
Dynamic Characteristics ◽  
Clean Energy ◽  
Energy Development ◽  
Stable Operation ◽  
Storage Unit ◽  
Pump Turbine ◽  
Characteristic Model ◽  
Pumped Storage

Hydropower is a kind of clean energy, which can effectively reduce the consumption of fossil energy and is one of the main fields of new energy development. Pumped storage power station not only provides a solution for storing electric energy and generating excess, but also is a clean, efficient, economical and safe power system regulation method with high quality. Accurate modeling of a pump-turbine, as the core equipment of a pumped storage unit, is the key to safe and stable operation of the pumped storage unit. At present, a method of simplifying the external characteristics of a pump-turbine into a first-order linear model is widely used, which cannot effectively and accurately reveal the nonlinear dynamic characteristics of the unit in transition process. In order to meet the demand of high-precision simulation of the unit, a new method of identifying Taylor series expansion considering nonlinearity based on the torque characteristic formula and the flow characteristic formula is proposed, which is applied to the pump-turbine external characteristic model, and retains the second derivative term, making the model a second-order nonlinear model, and thus, the pump-turbine model becomes a nonlinear model. The nonlinear model established is used to simulate the load increase and load rejection of the unit, and the results are compared with those for the linear model. The comparison shows that the nonlinear model established for the pump-turbine can reveal the dynamic response of the unit more effectively and accurately than the linear model, and provide a further guarantee for the safe and stable operation of pumped-storage units, which is of great significance to hydropower energy development.

scholarly journals Three-Dimensional CFD Simulations of Start-Up Processes of a Pump-Turbine Considering Governor Regulation

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8507
Author(s):  
Zhiyan Yang ◽  
Yongguang Cheng ◽  
Ke Liu ◽  
Xiaoxia Hou ◽  
Xiaoxi Zhang ◽  
...  
Keyword(s):  
Rotational Speed ◽  
Three Dimensional ◽  
Load Condition ◽  
Internal Flow ◽  
Pump Turbine ◽  
Characteristic Region ◽  
Start Up ◽  
Speed Fluctuation ◽  
Pumped Storage ◽  
Cfd Method

The pumped-storage power station is an efficient stability regulator of the power grid. However, due to the instability of the pump-turbine in the S-shaped characteristic region, rotational speed fluctuation is easy to occur in the speed no-load condition, making synchronization with and connection to the grid difficult. To investigate the key factors of these difficult grid connections, the start-up processes of a practical pump-turbine under the lowest head condition were simulated by using the three-dimensional CFD method, in which the governor regulating equations with different regulating parameters were integrated successfully. The results show that the working points oscillate with the fluctuations of rotational speed, discharge, and torque, and different regulating parameters have a significant influence on the dynamic histories. In addition, the internal flow patterns, especially the backflows at the runner inlet, keep apparent values at the middle span (0.5 span) but have regular transitions near the shroud side (0.7–0.8 span). The faster the guide vanes adjust, the faster the backflows change, and the larger the macro parameters fluctuate. Overall, the instability of the start-up is the result of the periodical evolutions of backflows at the runner inlet, because the trend and period of the radial velocities at different inlet span locations are consistent with those of the discharge.

scholarly journals Failure Analysis of Heat Exchangers with a Valid CFD Simulation

2021 ◽  
Author(s):  
Ádám Sass ◽  
Alex Kummer ◽  
Zsolt Ulbert ◽  
Attila Egedy
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Cfd Simulation ◽  
Flow Characteristics ◽  
Industrial Process ◽  
Infrared Camera ◽  
Stable Operation ◽  
Tubular Heat Exchanger ◽  
Surface Measurements ◽  
Study Heat Transfer

Energy efficiency, safety and stable operation of units are the most crucial aspects in every industrial process. In this study, Computational Fluid Dynamics (CFD) simulations were used to study heat transfer in a laboratory-sized tubular heat exchanger. A partly 2D axisymmetric and mainly 3D model of the heat exchanger was created and validated with several simulation in different operating points of heating capacity and volume flow. The results of the simulations were compared to experimental data to validate the model. The inlet and outlet temperatures were measured with Pt100 temperature probes, and the surface temperatures were measured with an infrared camera. The heat transfer coefficient was determined based on the surface measurements The validated model was applied for the investigation of performance losses of heat exchanger due to fouling caused by particle deposits along the tube which caused reduced heat transfer surface or performance and a failure of heating wire which caused reduced heating performance, hence altered heat and flow characteristics through the equipment. The results provide useful information not only in the design processes but the operational lifetime as well.

scholarly journals Axial Force Analysis of the Support Bracket of Pumped Storage Unit

2021 ◽  
Author(s):  
Buchao Xu ◽  
Weiqiang Zhao ◽  
Wenhua Lin ◽  
Zhongyu Mao ◽  
Ran Tao ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Axial Force ◽  
Cfd Simulation ◽  
Operating Conditions ◽  
Stable Operation ◽  
Axial Loads ◽  
Storage Unit ◽  
Maximum Deformation ◽  
Pumped Storage ◽  
Variation Rule

During operation, the support bracket is the main part to withstand the axial loads of the pumped storage unit. Moreover, the effects of axial loads including the hydraulic thrust of runner flow and the weight of runner body may cause the support bracket deformation and fatigue damage. For the safe and stable operation, the simulation of the axial force and the structural analysis of the support bracket of a pumped storage unit was carried out in this paper. The CFD simulation result has revealed the variation rule of the axial force in different operating conditions. Using ANSYS Mechanical, the static stresses and deformation of support bracket with axial loads were calculated. The results release the location and variations of maximum stress and maximum deformation caused by the axial loads. By comparing the predicted maximum axial force with the admission force calculated by the structural analysis, it is found that the axial force of the researched machine is within the safe range. This study provides the reference for the safety and stable operation of the pumped storage unit.

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