Numerical Simulation of Gaseous Hydrocarbon Fuel Injection in a Hypersonic Inlet

摘要

The performance of gaseous hydrocarbon/air mixing in the inlet of a scramjet is investigated in this paper. Thentwo-oblique-shock mixed-compression inlet configuration is selected, and cantilevered ramp injectors, designed tondeliver rapid mixing in a high-enthalpy flow, are placed strategically near the leading edge of the inlet. Air inflownconditions correspond to aMach 8 flight at a dynamic pressure of 67,032 Pa at a 28.6 kmaltitude.The objective of thisnstudy is to evaluate the impact of inlet geometrical parameters, fuel-injection properties, and injector dimensions onnthemixing efficiency. Both light (CH4) and heavy (C12H24) hydrocarbon fuels are considered. The analysis of three-ndimensional steady-state flowfields is undertaken numerically, using theWARP code.WARP solves themultispeciesnFavre-averaged Navier–Stokes equations, which are closed by the Wilcox k-! turbulence model. The numericalnresults indicate that a mixing efficiency of up to 95.8%can be achieved with a low risk of premature ignition. Inletncompression ratio, fuel-tank stagnation temperature, and fuel/air equivalence ratio are all identified as having ansignificant influence on inlet fuel-injection performance. The applicability of the cantilevered ramp injector to thenMach 8 hydrocarbon inlet is validated and justified.