Large-eddy/Reynolds-averaged Navier–Stokes simulation of a supersonic reacting wall jet

Abstract

This work presents results from large-eddy/Reynolds-averaged Navier-Stokes (LES/RANS) simulations of the well-known Burrows-Kurkov supersonic reacting wall-jet experiment. Generally good agreement with experimental mole fraction, stagnation temperature, and Pitot pressure profiles is obtained for non-reactive mixing of the hydrogen jet with a non-vitiated air stream. A lifted flame, stabilized between 15 and 20 cm downstream of the hydrogen jet, is formed for hydrogen injected into a vitiated air stream. Flame stabilization occurs closer to the hydrogen injection location when a three-dimensional combustor geometry (with boundary layer development resolved on all walls) is considered. Volumetric expansion of the reactive shear layer is accompanied by the formation of large eddies which interact strongly with the reaction zone. Time averaged predictions of the reaction zone structure show an under-prediction of the peak water concentration and stagnation temperature, relative to experimental data, but display generally good agreement with the extent of the reaction zone. Reactive scalar scatter plots indicate that the flame exhibits a transition from a partially-premixed flame structure, characterized by intermittent heat release, to a diffusion-flame structure that could probably be described by a strained laminar flamelet model.

Incipient thermal choking and stable shock-train formation in the heat-release region of a scramjet combustor. Part II: Large eddy simulations

“…35. The experiment has about 8% uncertainty in the estimated ER [13], and thus the cases at reported ERs of 0.34 and 0.33 (lower by 3% and 6%, respectively) actually fall within the margin-of-error in terms of the ER.…”

“…For example, the LES studies of the HyShot II scramjet by Fureby, Chapuis and co-workers [22,23] solved transport equations for the species at the macro-level using a partially stirred reactor model to close the chemical source terms. Similarly, the LES of Edwards et al [35] solved macro-level transport equations, but without any special closure for the source term. The chief difficulty in applying a flamelet model to supersonic combustion is the hydrodynamically induced variations in pressure and enthalpy (due to, e.g., shock waves, wall-cooling, etc).…”

Turbulence / Chemistry Interactions in a Ramp-Stabilized Supersonic Hydrogen-Air Diffusion Flame

“…The CARS also predicted significant amounts of cooler fluid at x/H = 6 which were mostly absent at the other three data planes. Figures 26,27,and 28 show the flamelet maps given in Figure 23 for x/H = 3, 6, and 12, respectively, projected along a third axis forχ. These plots were developed by sorting each scatter point into a particular bin of scalar dissipation rate.…”

Investigation of Subgrid Closure Models for Finite-Rate Scramjet Combustion

“…To address this issue, the initial left-and right-states (fourth order accurate) are blended with the final monotonicity-preserving states (states with added dissipation) using the vorticity / divergence function proposed by Ducros et al 28 These blended left-and right-states are then given as input to the LDFSS scheme to calculate the interface inviscid fluxes. Further details about this scheme, termed as Low-Diffusion PPM (LD-PPM), can be found in Edwards et al 29 Time accuracy is achieved using a planar relaxation sub-iteration procedure, which is based on the Crank-Nicholson time integration method. The method is described in detail in Edwards et al 29…”