Zonal Hybrid Reynolds-Averaged Navier–Stokes/Large-Eddy Simulation of a Hydrogen-Fueled Scramjet Combustor

A zonal hybrid Reynolds-averaged Navier–Stokes/large-eddy simulation framework is implemented to investigate the diffusion combustion of hydrogen–air in a model scramjet combustor. The computational domain is segregated into Reynolds-averaged Navier–Stokes and large-eddy simulation regions. An upwind convective flux discretization method and shear-stress transport turbulence models are applied to the Reynolds-averaged Navier–Stokes region, and the low-dissipative convective flux discretization method and improved delayed detached-eddy simulation are applied to the large-eddy simulation region. To generate turbulence at the Reynolds-averaged Navier–Stokes/large-eddy simulation interface, a synthetic-eddy method is employed. The geometries and boundary conditions of the model scramjet combustor are based on an experiment conducted at German Aerospace Center. The turbulent hydrogen diffusion flame is modeled using the steady flamelet approach. A total of nine computation cases are examined to analyze the influence of the numerical methods. As a result, the zonal hybrid method using the low-dissipative convective flux discretization method and synthetic-eddy method shows the best agreement with the experimental data in terms of quantitative temperature and rms velocity fluctuation profiles.