Stress analysis of runner blades in pump-turbine start-up process

In order to study the influence of fluid flow on the blade load in the runner region during the startup process of the pump turbine, the reversible pump-turbine in a domestic pumped storage power station is studied. Based on Realizable k-ε turbulent model, the UDF in fluent is used to control the movement of the active guide vanes in the starting process. Based on the dynamic and sliding grid method and combined with the speed change of the iterative computer group in the internal flow field of the reversible pump-turbine in the start-up process, the unsteady flow of the whole passage of the pump-turbine is calculated. Results show that the results of the simulation calculation are in good agreement with the theoretical research. The simulation calculation method is accurate and feasible for startup process of the pump turbine. During the start-up process, in the 0-5 s time interval, vortices distributed along the circumferential direction are distributed in the flow channel. With the increase of the opening and the optimization of the flow conditions of the runner blade, the blade vortex gradually decreases and then disappears. During the start-up process, the incoming flow impacts with the runner blade working face and forms a high pressure zone, which causes concentrated pressure load at the inlet position of the blade, resulting in a large difference in pressure between the working face and the back of the blade. During the start-up process, the impact of the incoming fluid on the blade working face is the main cause of the blade pressure load concentration and the blade vortex. © 2022, Solar Energy Periodical Office Co., Ltd. All right reserved.