Analysis of the three-dimensional transient flow in a scroll refrigeration compressor

Abstract

To optimise a scroll compressor design for better performance and reliability, an understanding of the detailed mechanism of the unsteady flow inside a scroll compressor is essential. In this paper, a three-dimensional transient flow model of a scroll refrigeration compressor operating with Refrigerant-22 was established. Dynamic hexahedral orthogonal grids were generated and updated during the solving process to ensure adequate grid layers at the tiny radial clearance of 30μm. The simulated results were validated experimentally. Furthermore, the flow mechanism and characteristic under a pressure ratio were analysed in detail. The asymmetrical distributions of the parameters and vortexes were mainly caused by the asymmetrical suction flow passage and movement of the orbiting scroll. Special flow phenomena such as ‘cut-off’ led to a sharp decrease of the suction mass flux at a crank angle of 200°. The leakage flow resulted in inhomogeneous temperature and velocity distributions in the working chamber. The influence of leakage flow on the pressure distribution was weaker than that on the temperature distribution. The maximum velocity of the leakage fluid reached 194.14ms−1. The pressure and temperature of the leakage fluid first decreased sharply and then recovered when it flowed through the radial clearance.