The Relationship between Contraction of the Ejector Mixing Chamber and Supersonic Jet Mixing Layer Development

Abstract

Supersonic mixing layer development seriously impacts on the performance of an ejector, and the effect of mixing chamber contraction angle on supersonic jet mixing has been poorly studied. Numerical simulations are applied to investigate the effect of the mixing chamber contraction angle (φ) on the performance of a central ejector and supersonic mixing layer development pattern. The main findings of this study are as follows: the non-mixed length (l) is reduced by 22.12% when the mixing chamber contraction angle (φ) increases from 2° to 6°. Meanwhile, the secondary stream mass flow rate (ms) is reduced by 35.02%, and the total pressure loss is decreased by 18.37% at the outlet. l is positively correlated with ms and negatively correlated with the mixing layer thickness (σ). The mixing layer thickness (σ) grows highly linearly before the secondary flow is covered completely. The pressurization (P0δ/P0s) performance of the mixing layer will be progressively weaker than the total pressure loss because of the complex shock structure.