Working mechanism and characteristics analysis of a novel configuration of a supersonic ejector

Abstract

The growing awareness of utilizing low-grade energy has encouraged the scientific community to conduct research on supersonic ejectors. Most previous studies have investigated on the geometry parameters or profiles of supersonic ejectors, but few studies have focused on improving the ejector configuration. This paper presents a novel configuration of a supersonic ejector which has the advantage of better performance than the conventional ejector in double-choking mode. First, the novel configuration and its working mechanism are presented, and the entropy generation of the primary fluid is compared theoretically between the novel and conventional configurations. Second, validation of the novel configuration mechanism is performed using CFD. The velocity and pressure distribution, performance characteristics, and entropy generation at different outlet pressures are presented and analyzed in comparison to the conventional ejector. The normal shock intensity in the novel configuration is reduced and the total entropy generation decreased, thereby improving the ejector's performance. Finally, the impact of the geometric parameters of the novel configuration is evaluated, pointing out its limits and the need of further investigation and experimental studies for optimal design.