Study on hydraulic characteristics of large vertical axial-flow pump used as constant frequency power generation

In order to study the stability of power generation in reverse of a pumping station unit, the computational fluid dynamics simulation and finite element analysis of the whole passage has been carried out, to study the pressure pulsation and stress distribution law under the condition of power generation in reverse, and compared with them in pump mode. The simulation results showed that, under the condition of power generation in reverse, the pressure pulsation of each monitoring point in front and at back of the runner were higher than that under pump mode. The most amplitude of pressure pulsation was about twice as large as the pump mode, increased gradually from hub to rim. The flow was seriously affected by the rotating runner. The internal frequency of pressure pulsation was blade frequency. The results of fluid–solid coupling showed that the stress mainly concentrated on the root of the pressure side and the suction side of the blade, and the maximum equal stress appeared on the suction side of the blade. The maximum stress and strain value under the condition of power generation in reverse were 20% higher than that under pump mode, and the maximum stress was about twice.