Investigation of the unsteady characteristic in a scroll compressor of a heat pump system for electric vehicles

The scroll compressor is widely utilized in the heat pump air-conditioning of electric vehicles. However, the scroll compressor cannot show a good performance in low ambient. This work presents three-dimensional transient simulation models of no-injection and vapor-injection scroll compressors to investigate the internal flow characteristics using R134a. The different shapes of the vapor-injection pipe holes, including the center distance of two interlinked circular and connection structures, are also discussed in relation to the scroll compressor performance. The results reveal that the isentropic efficiency of the scroll compressor increased by 8.51 similar to 9.35% and the discharge temperature decreased by 6.00 similar to 9.08 K when the different shapes of vapor-injection pipes are added. When the center distance of two interlinked circular injection holes grows, the compressor's isentropic efficiency increases and the discharge temperature decreases. Additionally, the number of eddies decreased when the double-arc interlinked construction is used for the vapor-injection pipe. Overall, it has been discovered that vapor-injection technology can improve the isentropic efficiency of a scroll compressor while also lowering the discharge temperature. Moreover, using double-arc interlinked injection holes could achieve better comprehensive performance.