Abstract: The suction gap at the bottom of the stationary disc in the scroll compressor is designed to increase the suction flow rate of the compression chamber and have a significant impact on the suction process and performance. To study the influence of suction gap, CFD simulation was used to study the effects of different suction gaps on the unsteady pressure field, flow distribution, and performance. The results showed that the suction pressure and flow rate showed unsteady fluctuations. As the suction gap decreased, the suction pressure continued to increase, and the suction flow rate continued to decrease. The increase in suction pressure led to a decrease in compressor power and an overall increase in energy efficiency. Through whole machine testing, it was found that under DOE-B condition, when the suction gap was from present to absent, the cooling capacity decreased by 0.70%, the input power decreased by about 1.01%, and the energy efficiency increased by about 0.32%. This verified the effectiveness of the established CFD simulation method, and the research can provide guidance for the optimization design of the suction process of scroll compressors.

Key words: Suction gap, Unsteady pressure, Flow rate, Scroll compressor, CFD computation