Laboratory–Scale 펌프수차 모델의 수차 모드에서 흡출관 내 와류 특성

Abstract

The pump-turbines as a flexible power generation facility have being operated within the off-design conditions for ensuring the constant power supply to respond to intermittent renewable energy sources such as solar and wind power. Especially, under the low flow rates of the off-design conditions, the complicated internal flows with vortex ropes in the draft tube destabilize the pump-turbine system. Therefore, in order to expand the reliable operating range, it is necessary to understand the internal flow and pressure phenomena under low flow rate conditions of the pump-turbines. In this study, the experiments of a laboratory-scale pump-turbine model were conducted to investigate the vortex characteristics according to the cavitation number at the turbine mode under low flow rate condition. Based on the experimental results, a two-phase (water and vapor) unsteady state RANS analyses were performed using SAS-SST turbulence model. Experimental and numerical investigations showed that the behavior and magnitude of visible vortex rope in the draft tube were in good agreement, and when the visible vortex rope was generated, a relatively higher swirl number and unsteady pressure were shown in the draft tube.