Design exploration on the mixing augmentation induced by the oblique shock wave and a novel step in a supersonic flow

Abstract

The mixing process in the supersonic flow is very important for the engineering implementation of the scramjet engine, and many novel mixing augmentation schemes have been proposed and investigated in the past few years. In this paper, the combination between the oblique shock wave and a novel step has been proposed to promote the mixing process between the supersonic airflow and the fuel, and the oblique shock wave has been induced by a ramp located on the upper wall of the channel. The impacts of the jet location and the jet pressure ratio have been both evaluated in order to explore their influences on the mixing enhancement mechanism. The obtained results show that the oblique shock wave is beneficial to prolong the residence time of the hydrogen in the supersonic flow, and the hydrogen distribution moves upstream with the oblique shock wave. At the same time, when the jet pressure ratio is large enough, the recirculation zone formed downstream of the step would increase, and this is beneficial for the mixing process between the fuel and the air as well. This may imply that the proposed combination scheme is a good candidate for the fuel mixing augmentation strategy, and its physical mechanism should be explored much deeper in the future, especially for its three-dimensional effect.