1 A Critical Review of Scramjet Combustion Simulation

A review of scramjet combustion simulation is provided in this paper. The topics covered include the fundamental problem of supersonic mixing layers, high-speed combustion modeling efforts, and actual calculations of realistic scramjet combustors. The review shows that the RANS approach dominates the turbulence modeling of the system, with only a handful of LES work. Also, virtually all the numerical works are based on low-order schemes, and the combustion models that have been used for realistic simulations solve the species evolution equations with assumed PDF closures, although there seems to be a growing use of the flamelet methods. Spray modeling for scramjet combustion has not received enough attention. Nomenclature 2D = two-dimensional ζ = variance of fluctuating vorticity 3D = three-dimensional κ = parameter in the MUSCL scheme Cp = specific heat at constant pressure μ = absolute or dynamic viscosity CFL = Courant-Friedrichs-Lewy ρ = density D = diffusion coefficient ζ = shear stress tensor DES = detached eddy simulation φ = function of species and/or temperature, equivalence ratio k = kinetic energy of turbulence χ = mixture fraction dissipation rate P = probability density function (PDF) = reaction rate Prt = turbulence Prandtl number p = pressure Subscripts S = stoichiometric coefficient airc = inlet to combustor Sct = turbulence Schmidt number airct = total (stagnation) at inlet to combustor T = temperature f = fuel t = time i = coordinate direction; 1, 2, 3 TVD = total-variation diminishing j = coordinate direction; 1, 2, 3 u = velocity k = index for species Y = mass fraction o = oxidizer Z = mixture fraction p = products δ = Kronica delta ∞ = free stream ε = kinetic energy dissipation rate I