Modeling scramjet supersonic combustion via Eddy Dissipation Model

Scramjet technology has gained considerable interest in multi-stage to orbit design concepts due to its reusability and high specific impulse at high-Mach regimes. The aim of the present work is to introduce Reynolds Averaged Navier-Stokes CFD calculations in the design phase of scramjet vehicles and increase the fidelity of engine performance assessment. The turbulence-chemistry interaction is described by the Eddy Dissipation Model (EDM) introduced by Magnussen and Hjertager, which assumes that turbulent motions and not chemistry is the main driver in the rate of combustion. The use of the EDM is explored by application to three hydrogen–fueled scramjet test cases. The model requires constants to be prescribed, which are found to be case dependent. Optimal values for the cases simulated are discussed along with appropriateness of the model for general design simulations. The advantage in computational cost is demonstrated by comparison with a no-model finite-rate chemistry approach.