Fluid-structure coupling analysis of inlet ball valve on pumped-storage power station under extreme conditions

Abstract

While pumped storage power stations (PSPSs) provide clean energy, they are also facing many problems of safe operation. Inlet ball valves bear the brunt of the impact and disturbance from upstream pressure pipeline under extreme conditions on PSPSs. Artificially change the wicket gate and ball valve closing laws can improve the extremums of key indicators. However, the internal flow field in ball valves is complex, and the internal flow field interacts with the external structure. The performance impact studied only by the indicators of the ball valve inlet and outlet is far from enough. In this study, three-dimensional flow field simulation of an inlet ball valve on PSPS was carried out, and the Realizable k-ε turbulence model was selected to simulate the pressure and velocity changes of the flow field inside the ball valve under load rejection conditions. Based on the theory of fluid-structure coupling and CFX dynamic grid, the response characteristics of the ball valve mechanical structure after being subjected to transient flow field were studied, the distribution of related performance parameters of the structure was obtained, and the mechanism that causes stress, strain and total deformation was analyzed. This study found that the ball valve structure is significantly affected by the three-dimensional transient flow of water under extreme conditions of load rejection. The safety of the ball valve can be enhanced by setting expansion joints and strengthening the base.