Influence Of Blade Parameters On Hydraulic Performance Of Pump Turbine Runner

In recent years,the pace of development of pumped storage power stations is accelerating.As the core component of pumped storage power stations,the pump turbine will be operated both as a pump and as a turbine,the hydraulic performance of the pump turbine has a direct impact on the generation efficiency of the power plant.The runner is the "heart" of the pump turbine,the head of pump and the head of turbine have important influence on the design of runner.At present,the pump turbine is developing towards the direction of high water head,and the design difficulty is also increasing.Meanwhile,it is urgent to strengthen the work capacity and hydraulic performance of the runner.Therefore,the selection of a runner with good performance plays an important role in ensuring the performance of the pump turbine.From the perspective of blade parameters,the influence of blade parameters on the performance of pump turbine runner was discussed in this paper,which will provide a reference for the design of pump turbine runner.In this paper,the TURBO-design software was used to design the runner blade.This software is based on the design method of 3D inverse problem.In the design process,the basic design parameters of the runner blade,such as head,flow rate,rotational speed etc.should be determined.The blade shape can be obtained by adjusting the load distribution on the blade and the angle of the high pressure edge.When the pump turbine is running as pump,it is difficult to satisfy both the lift characteristic and the cavitation characteristic at the same time,so the runner blade is designed according to the pump condition,while the performance of the turbine is verified by CFD.In order to study the influence of the blade's load distribution on the cavitation performance of the pump conditions and the influence of the angle of blade high pressure side on the pressure pulsation in the blade-less space of the turbine,the runners with specific parameters were selected for the study.The structured grid was used to for full flow channel meshing,and the RNG k-? turbulence model was selected for numerical calculations.The calculation results show that the load distribution modes of forces in the middle of the crown and on back of the bottom ring can effectively improve the efficiency characteristics and cavitation characteristics of the pump operating conditions;the inclination of the blade high-pressure side can improve the efficiency characteristics of the turbine operating conditions and the inlet flow state of the runner,thus improving the pressure pulsation performance in the blade-less space;under the turbine design conditions,applying large-angled rotor rather than a small-angled rotor can achieve a smaller pressure pulsation amplitude in the blade-less space;when the operating conditions are gradually deviated to the small flow conditions,applying the negative-inclined rotor can realize the minimum increase in the amplitude of the pressure fluctuation amplitude in the blade-less space,so the small negative-inclined rotor can adapt to a wider range of operating conditions.The above conclusions show the change of the blade parameters will have a great influence on the hydraulic performance of the runner of the pump turbine,which means the study of this topic is of great significance to the design optimization of the runner of the pump turbine.