Effect of Combustor Configuration on Flow and Combustion in a Scramjet Engine

摘要

The experimental research described previously indicates that combustor geometry, such as constant cross-sectional part length or cavity configuration, has a strong influence on the flow and combustion inside a scramjet engine. The intake is easier to start when the engine length is shorter. The existence of a cavity may.be an obstacle for the intake start. Especially, shorter cavities bring more chance of intake start, because the pressure rise downstream of the cavity is smaller for shorter cavities. L/D or 9 does not have a direct influence on the intake start. Cavity length is the most important parameter, because it also affects combustion efficiency. A shorter cavity provides higher combustion efficiency in the range of (ψ) = 0.17-0.21. In this study, a cavity with D = 8 mm, L = 2D),and θ = 90 deg is the best in that (ψ)＞ range in this regard. The test model falls into unstart with (ψ) = 0.24 for L = 7.8D geometry and (ψ) = 0.31 for the L = ID model.