Numerical study of transverse hydrogen injection in high-speed reacting crossflow

A high-speed compressible solver capable of solving detailed chemical reaction mechanisms is developed by coupling the open-source computational fluid dynamic toolbox OpenFOAM((R)) and Cantera 2.5.0. A sonic hydrogen jet discharging from a circular injector into a high enthalpy supersonic crossflow over a flat plate is selected as a test case for the developed solver. The incoming boundary layer is laminar, and an adverse pressure gradient-induced transition is expected due to transverse injection. The test case is selected to serve two purposes. First, to validate the developed solver. Second, to inspect the capability of Reynolds-Averaged Navier-Stokes (RANS) in predicting the flame characteristics in high-speed flows involving laminar to turbulent transition. The present study features three-dimensional RANS simulations with Shear Stress Transport (SST) k-? and Langtry-Menter SST k-? turbulence models, with three values of inlet turbulent intensity: I = 0.5, 1, and 2. Analysis showed that laminar to turbulent transition plays a significant role in the resulting flame structure. A fully turbulent SST k-? model showed several discrepancies from the experiment, especially near the boundary layer. On the other hand, the Langtry-Menter SST k-? model predicts transition onset and hence the flame structures accurately. Furthermore, the transition onset and the flame structure strongly depend on I. The low-velocity recirculation regions near the injector aid in flame stabilization upstream of the injector. At the same time, the horseshoe vortex dictates the flame spread in a spanwise direction. The reflected shock-boundary layer interaction helps in flame stabilization downstream of the injector.