Research On Hydraulic Performance Of 700m Super High Head And Large-Scale Pump Turbine

With the progress of science and technology,the pump turbine is developing to high head and large capacity.However,due to the short time of research and development of pump turbines in our country,it has not involved in the development of pump turbine in ultra high lift stage.Based on the Dunhua pumped storage power station project,the hydraulic performance of 700 meters extra high lift and large-scale pump turbine has been studied.The main contents are as follows:Based on the technical statistical method,the statistical relationships between specific speed and pump head,geometric parameters and specific speed have been studied and established.The geometric parameters include the diameter of the runner,the height of the guide vane and the diameter of the pitch circle,etc.Based on the above research results,the specific speed and geometric parameters of the project were fully demonstrated,selected and analyzed.Macroscopically guarantee the results of hydraulic development should not deviate from the actual requirements of engineering application and the hydraulic performance level of final R & D results by the demonstration and selection results of design parameters.Based on the results of parametric demonstration,the hydraulic performance of runner was developed.The total of 7 runners with different parameter schemes have been developed.From the two aspects results of the numerical calculation and model test,the main hydraulic performance indicators of the runner that with different meridional flow channel,different blade number,different diameter ratio,different high pressure side shape and different blade inclination angle,have been compared and analyzed.And The internal flow field of each runner scheme is numerically analyzed.Based on the development of the each scheme runner,the design parameters of the runner with 700 meters super high head pump turbine are put forward.The development results of each program runner can satisfy the main performance requirements of R & D projects.Based on the hydraulic development results of the runner scheme,for the energy characteristic of pump,the hump characteristic of pump and the "S" shape characteristic of turbine,the numerical simulation of full flow passage and performance prediction were carried out.The method of constant calculation is adopted in numerical calculation.The numerical calculation of external characteristic curve and model test result are compared and analyzed,and the accuracy of external characteristic curve prediction is evaluated.By analyzing the flow field of key characteristics,it is found that the decrease of head lift in the Hump zone and the deterioration of hydraulic stability in the "S" zone are closely related to the increase of eddy dissipation.In addition,the influence of flow hysteresis on the outer characteristic curve of the hump is reproduced by numerical simulation.The numerical results can well predict the hydraulic performance of the R & D resultsBased on the model test results of pressure fluctuation characteristics for each runner scheme,the influence factors of pressure fluctuation in vaneless space were studied deeply.For study the influence of the vaneless pressure fluctuation,the meridional flow channel,the number of runner blades,the diameter of the runner,the diameter of the guide vane pitch circle,the shape of blade lead edge and the inclination angle of blade lead edge are analyzed.The mathematical method of normalization is introduced,and the variation law of pressure pulsation in vaneless space with flow rate and operation head of different runner schemes is analyzed in detail.The amplitude of pressure pulsation in the vaneless region is closely related to the design parameters of the meridional flow passage,the number of blades and the diameter of the pitch circle.The application of the results of pressure fluctuation in the vaneless space improves the hydraulic stability level of the Dunhua unit.In this paper,the hydraulic development results of a 700 m super high head pump turbine with high efficiency and high stability index are studied.And the research production have been successfully applied in the unit construction of Dunhua project.