Influence investigation of friction on supersonic ejector performance

The effects of internal surface roughness on ejector performance were investigated by dividing the ejector into five categories: the nozzle, suction chamber, mixing chamber, constant-area section and diffuser with the computational fluid dynamics (CFD) technique. Each section was analyzed with the experimental values obtained from the ejector refrigerant platform by using replaceable nozzles with different levels of roughness. It was ascertained that friction has a noticeable influence on the performance of the ejector; therefore, an increase in the roughness level will essentially lead to a decline in the ejector's working performance. Furthermore, the constant-area section and diffuser have the most significant impact on ejector performance. The correlations regarding the friction influence for numerical calculations and the polishing process of ejector manufacturing are also essentially discussed.