Stress Characteristics Analysis of Key Stationary Structural Components of Pump-Turbine Units Under Extreme Conditions

The endurance and stability of the key stationary structural components are extremely important for the safe operation of the pump-turbine unit and the pumped storage power station. In order to reduce the stress level on the stationary structures during the design phase, the 3D finite element simulations of a large high-head pump-turbine unit under extreme conditions have been performed with a series of improvements on the design model. The full-scale 3D model of the stationary structures of the pump-turbine unit including the head cover, stay ring, stay vanes and bottom ring was built and meshed properly. After applying the pressure load of the extreme conditions on the structural finite element model, the stresses of the stationary structural components were calculated. According to the simulation results, all the locations where the maximum stress was above the material tensile strength can be improved. The novel optimized design approach developed in this investigation can highly reduce the design time cost and improve the endurance and stability of the designed structures to withstand all possible pressure loads under various steady and transient operating conditions. It also offers a valuable reference to the design of other types of hydraulic machinery.