Internal Flow and Cavitation Analysis of Scroll Oil Pump by CFD Method

Abstract

In this study, a three-dimensional model with actual clearances was established for a scroll oil pump, and the internal flow was simulated by the CFD method. The internal flows at different rotation angles were studied, and the cavitation and pressure pulsation in the scroll pump under different working conditions were analyzed. The results show that the flow in the two working chambers of the scroll pump is asymmetric due to its structural characteristics and motion mode. The high-pressure pulsation occurs in the working chamber during the end of the suction and the beginning of discharge. Under the action of high-pressure difference, there is a high-speed jet in the clearance between the orbiting and fixed scrolls, which causes a large area of cavitation downstream of the clearance. Under a low suction pressure, cavitation intensifies with the increase in rotating speed, which leads to a decrease in volumetric efficiency. It can effectively improve cavitation by increasing the suction pressure and volumetric efficiency of the pump. The pressure pulsation can be effectively improved by increasing the axial clearance and reducing the rotating speed. The method of reducing pressure pulsation by shortening the scroll profile is proposed.