Effect of the ambient medium parameters on ignition and combustion of a supersonic hydrogen jet expanding into a still space

Results of numerical simulations of mixing, ignition, and combustion of a cold supersonic (М$_{jet}$ = 1.46) hydrogen jet injected coaxially into an annular supersonic (М$_{air}$ = 1.86) jet of hot vitiated air expanding into a still space are reported. The simulations are performed within the framework of the ANSYS Fluent 2020 R1 software in a transient two-dimensional axisymmetric approach based on the Reynolds-averaged Navier–Stokes equations supplemented with the $k$–$\omega$ SST turbulence model and a detailed mechanism of hydrogen combustion in air. The geometry and simulation parameters are chosen to be those of the experiment of Cohen and Guile (1969), whose data were used for verification of the numerical algorithm. The structure of the reacting jet is studied, and the hydrogen combustion efficiency is evaluated for various values of the jet pressure ratio. The instantaneous, mean, and RMS components of the main gas-dynamic quantities and species mass fractions in the reacting mixture are obtained.