A Method of Detecting Self-Starting Ability of Hypersonic Inlets: A Numerical Investigation

Abstract

It is still a challenge to accurately predict the self-starting ability of a hypersonic inlet. Re-start of an inlet after a mechanically throttling induced unstart is proof of its self-starting ability at the test conditions. The authors have proposed a method to detect an inlet self-starting ability in a shock tunnel by pre-setting a blockage with a suitable weight in the inlet. The blockage nearly closes the flow path to unstart the inlet at the initial running phase, and then it also can be blown out of the flow path to detect the ability of the inlet to re-start in the test flow durations of the shock tunnel. To thoroughly study the details and improve the method of detecting the ability of an inlet to self-start, the motion of the blockage was simplified as a rigid body with one degree of freedom, and then two-dimensional numerical simulations were conducted by applying a dynamic mesh technique of layering. The results indicate that the mass of the blockage plays an important role in the detecting process, which determines the blockage duration. Although the blockage duration does not affect the ability of an inlet to re-start, a suitable blockage which can be pre-estimated by an accelerating motion model is recommend.