Visualization of pressure distribution due to impact accompanying collapse of cavity on the vanes of mixed flow pump-turbine

In this study, the cavitation and the impact pressure on a vane at the time of the collapse of cavity in a horizontal movable vane type mixed flow pump-turbine were visualized and measured directly using a pressure-measuring seat (prescale film) changing the cavitation coefficient and rotating speed. As the cavitation coefficient k(d) became smaller, maximum cavitation pressure became higher and its location moved downstream. Even if k(d) was equal, the maximum pressure became higher as the rotating speed increased.