Study on the Performance of Pressure Balance Pipe of Pump-turbine

Abstract For pump-turbine, axial water thrust can cause damage to the unit. It is important to realise automatic levelling by using pressure balance pipe. To study the influence of the pressure balance pipe on the performance of the reversible pump-turbine, axial water thrust and pressure fluctuation have been carried out for reversible pump-turbine with different guide vane opening and different operating heads by numerical and experimental analysis. The unsteady simulation results for the full flow channel of the pump-turbine show that the 298 mm guide blade opening meets the test standards of flow and power. Furthermore, CFD tests were carried out for different water heads at 298mm guide vane opening. At last, under the typical working conditions of 298mm guide vane opening and 400 m water head, pressure fluctuation, the axial water thrust in the vaneless zone are analyzed.