Numerical investigation of pressure fluctuation for a mixed flow pump impeller and vanes diffuser

In order to investigate the effect of rotor-stator interaction between impeller and vanes diffuser on the pressure fluctuation of a mixed flow pump, the pressure fluctuations at three representative locations under the design condition are obtained, unsteady flow feature is analyzed by RNG kappa-epsilon turbulence model with sliding mesh technology. Experimental results show that there is the positive slope of head-flow performance curve under 0.6 and 0.85 design condition, which unsteady prediction is not seen based on Reynolds-averaged equation. The pressure fluctuation is analysed by the characteristics of amplitude and frequency, the amplitude of pressure fluctuation, which the maximum is in the rim of impeller outlet and the minimum is in the hub of impeller inlet, is gradually increasing along the hub to rim, the amplitude of monitoring points located the rim of impeller inlet and impeller and vanes diffuser is two times than the hub. The amplitude of pressure fluctuation, which the maximum is in the vanes diffuser outlet, is gradually increasing along impeller inlet to vanes diffuser outlet, while there is a low-frequency pressure fluctuation caused by unsteady flow in the vanes diffuser.