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

Sugen Tian,Guangbin Liu,Liansheng Li,Kairui Dong,Yuanyang Zhao,Qichao Yang

doi:10.3390/pr9101705

Sugen Tian, Guangbin Liu + Show 4 more

Open Access

https://doi.org/10.3390/pr9101705

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Journal: Processes	Publication Date: Sep 23, 2021
Citations: 2	License type: CC BY 4.0

Affiliation: Qingdao University of Science and Technology

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.

Highlights

As a result of its technical development in recent years, scroll fluid machinery has been used widely in compressors, vacuum pumps, and other related fields
To prevent the compression process in pumps, the profile of the scroll pump must be controlled within 1.5 circles
The results show that deep pressure pulsation occurs in the working chamber at the initial stage of liquid discharge [27]

Summary

Introduction

As a result of its technical development in recent years, scroll fluid machinery has been used widely in compressors, vacuum pumps, and other related fields. The process of pressurization and discharge of liquid is realized in scroll pumps. The results show that deep pressure pulsation occurs in the working chamber at the initial stage of liquid discharge [27]. The abovementioned studies only researched the liquid flow in scroll pumps by not considering the influence of axial clearance on volumetric efficiency. The performance and cavitation of the pump, influenced by rotating speed, suction pressure, the radius of rotation, and other parameters, were studied. To analyze the pressure changes in the working chamber by the CFD method, we set up five monitoring points (P1–P5) close to the wall of the fixed scroll plate, and the interval between the two monitoring points was 90◦.

Mesh and Boundary Conditions

Conclusions