Investigation on the performance and vapor injection characteristics of a scroll compressor for electric vehicles based on computational fluid dynamics approach

Abstract

The vapor injection scroll compressors demonstrate significant potential in heat pump air conditioning systems for electric vehicles, where their operational characteristics play a crucial role in determining the driving range of electric vehicles. In this study, a thermodynamic model of a vapor-injection heat pump system was developed, and 3D transient simulations were performed for scroll compressors with varying injection port shapes. Experimental validation confirmed the accuracy of the simulation results. The results show that under simulated conditions, the heat pump system achieves optimal performance when the injection pressure is 0.7 MPa, with the coefficient of heating performance reaching a peak of 4.2. Regions of low temperature and high velocity were observed around the injection ports, with their shapes and sizes influenced by the injection ports geometry. The mass flow rates at the outlet of single circle, double circle, and arcs plus lines injection port scroll compressors increased by 16.35 %, 39.10 %, and 61.85 % compared to the compressor without injection, while the discharge temperatures decreased by 4.68 K, 7.47 K, and 8.27 K, respectively. Furthermore, the scroll compressor with arcs plus lines injection ports exhibited the highest isentropic efficiency, improving by 25.23 % compared to the non-injection compressor. The vapor injection technology significantly enhances the efficiency and lifespan of scroll compressors, which is crucial for extending the driving range of electric vehicles.