Supersonic flow over a rearward facing step with transverse nonreacting hydrogen injection

This work involves an application of computational fluid dynamics to a problem associated with the flow in the combustor region of a supersonic combustion ramjet engine (Scramjet). In particular, a time-dependent, finite difference method is used to. solve the complete two-dimensional Reynolds averaged Navier-Stokes equations for the turbulent supersonic flow of air over a rearward-facing step, with transverse H2 injection downstream of the step. To delineate the purely fluid dynamic effects, the flow is treated as nonreacting; however, detailed binary diffusion of H2-air is included, along with a variable Lewis number. Results are obtained and compared for cases with and without H2 injection. The influence of the wall temperature boundary conditions (adiabatic vs constant temperature) is studied, and is shown to have little impact on the flow both near and far away from the wall. These numerical results are the first to be obtained for this flow geometry, expecially at,conditions germaine to a Scramjet. They demonstrate that such an application of computational fluid dynamics can be useful for the study of inlet-combustor interactions, and the flameholding potential of the rearward-facing step.