Performance and mixing process investigation of a novel mixing-enhanced ejector

Abstract

Ejector refrigeration systems rarely require electrical energy, satisfying the requirements of sustainable development and low carbon emissions. However, owing to the limitations of the operating conditions, the ejector performance is not sufficient, and there is an urgent need to improve the entrainment performance of the ejector. In this study, experiments and numerical simulations were performed on a conventional ejector, and the numerical simulation results were fitted with the experimental data. A numerical simulation was used to investigate the mixing process and entrainment performance of the novel mixing-enhanced supersonic steam ejector. The optimal values of lm = 120 mm and dc = 57.5 mm achieved the best entrainment ratio (0.778) for the novel ejector under 5%-tab blockage ratio. The results showed that the entrainment performance of the novel ejector improved by 51.1–54.7% and 10.5–12.3% compared to those of the conventional ejector and the conventional ejector with an adjusted mixing chamber, respectively. This was because the generated streamwise vortices entrained more secondary flow into the mixing chamber, and the mixing process between the primary and secondary flow avoided unnecessary kinetic energy loss, increasing the mixing efficiency and accelerating the secondary flow crashing out of the diffuser.