Numerical investigation and optimization on the micro-ramp vortex generator within scramjet combustors with the transverse hydrogen jet

Abstract

An effective fuel supply strategy with high mixing efficiency, large penetration depth and low stagnation pressure losses determines the overall performance of the scramjet (supersonic combustion ramjet) engine. In this paper, the transverse hydrogen injection flow field with a micro-ramp located upstream of the wall orifice has been investigated numerically based on the code validation. There are four design variables considered in the current study, namely the width, length, and height of the micro-ramp and the distance between the center of the wall orifice and the trailing point of the micro-ramp. Nine cases predicted by the three-dimensional Reynolds-averaged Navier–Stokes (RANS) equations coupled with the two equation k–ω shear stress transport (SST) turbulence model are used for parametric analysis, and the parametric analysis has been carried out by the extreme difference analysis approach. Three optimization cases are obtained, and they have different objectives, namely the minimization of the mixing length, the maximization of the penetration depth and the minimization of the stagnation pressure losses. The flow structures of all cases have been discussed and compared. The quantitative evaluation results of three optimization cases show that the extreme difference analysis approach is an efficient parametric analysis method, and it can obtain the optimal strategy for the micro-ramp within scramjet combustors with the transverse hydrogen jet.