Simulations of a cavity based two-dimensional scramjet model

Simulations of a cavity based two-dimensional scramjet model

This paper presents a computational fluid dynamics (CFD) study of non-reacting and reacting flows within a scramjet model, and for the latter the flow domain is fueled with liquid fuel and operated at shock tunnel flow conditions. This scramjet model includes an isolator, a combustion chamber and a diffuser duct. The liquid fuel is injected through lower surfaces before the cavity flame-holder. The primary goal of the study is to evaluate the detailed cavity based flame stabilization. Those CFDpredicted wall pressure distributions with available experimental data firstly to evaluate the simulation model, thus to understand underlying combusting flow physics. For the “combustion off” cases, as the distance of the corner plate increase, the boundary layer thickness of the downstream from the rear wall of the cavity increase; the entrainment air flow into the cavity and the recirculation zones in the cavity also vary with this distance changes. For the “combustion on” cases, the distance affects the position of the fuel rich regions and where the air and fuel mixture reactions occur. Despite short penetration depth of fuel injection from the simulation, the desired cavity flame stabilization has been partially achieved in the cavity flow field. The cavity flame stabilization provides a mechanism by which combustion can be achieved with mild intake compressions, which leads to greater intake efficiency (with less total pressure loss) and overall greater scramjet performance. Future work will continue to focus on the combustion instability optimized by exploring various types of cavity and corner plate configuration and cavity-based fuel injection system.