Characteristic Analysis of Pressure Fluctuation in a Three-Stage Rotodynamic Multiphase Pump

In order to investigate the pressure fluctuation in a three-stage rotodynamic multiphase pump developed by authors, a bench test is set which choose the mixture of water and air as medium. Nine monitors are set in the pump including the inlet of each impeller, the interfaces of the rotor-stator and the middle section of each impeller. It turns out that the minimum pressure fluctuation is located in the interfaces of the rotor-stator in each stage and the maximum is in the interface of two stages. The domain frequency is the blade passing frequency of the impeller and its multipliers and there is no higher frequency. The coefficients of the pressure fluctuation is first decreased and then increased with the increase of the inlet gas volume fraction at the same rotational speed. But it increases with the increase of rotational speed at the same inlet gas volume fraction.