Analysis of Internal Flow and Vibration Characteristics of Tubular Turbine Considering Dynamic Change of Liquid Level in Reservoir Area

Abstract

Abstract The tubular turbine of the tidal power station is often affected by different incoming waves in the actual operation, which seriously affects the operation performance. Based on this, the real tubular turbine including upstream and downstream reservoir areas was selected as the research object, and numerical wave generation was conducted using the inlet wave generation method. The second-order Stokes wave was used to study the flow condition and vibration characteristics of the turbine in the upstream reservoir area. The results show that under the action of second-order Stokes wave, the pressure amplitude is obviously increased compared with that without liquid level fluctuation, and the flow velocity in the internal flow field is accelerated. During the wave periods, the pressure values at the runner outlet, the draft tube inlet and outlet all show periodic changes, wave energy decays and the pressure gradually decreases and weakens periodically with the shift of position. The vortex belt of draft tube has the spiral characteristics in the wave process, which will produce more axial vibration and affect the output of the unit in actual operation. These findings have theoretical significance for the actual operation, maintenance and hydraulic design of tidal tubular turbines.