Steady-state and scale-resolving simulations have been performed for flow in and around a model scramjet combustor flameholder. Experimental data available for this configuration include velocity statistics obtained from particle image velocimetry as well as a limited number of scalar measurements using laser-induced breakdown spectroscopy. Several turbulence models were used for the steady-state Reynolds-averaged simulations, which included both linear and nonlinear eddy viscosity models. The scale-resolving simulations used a hybrid Reynolds-averaged/large-eddy simulation strategy that is designed to be a large-eddy simulation everywhere except in the inner portion (log layer and below) of the boundary layer. Hence, this formulation can be regarded as a wall-modeled large-eddy simulation. This effort was undertaken to not only assess the performance of the hybrid Reynolds-averaged/large-eddy simulation modeling approach in a flowfield of interest to the scramjet research community but also to begin to understand how this capability can best be used to augment standard Reynolds-averaged simulations. The numerical errors were quantified for the steady-state simulations and at least qualitatively assessed for the scale-resolving simulations before making any claims of predictive accuracy relative to the measurements. The steady-state Reynolds-averaged results displayed a high degree of variability when comparing the flameholder fuel distributions obtained from each turbulence model. This prompted the consideration of applying the higher-fidelity scale-resolving simulations as a surrogate “truth” model to calibrate the Reynolds-averaged closures in a nonreacting setting before their use for the combusting simulations. In general, the Reynolds-averaged velocity profile predictions at the lowest fueling level matched the particle imaging measurements almost as well as was observed for the nonreacting condition. However, the velocity field predictions proved to be more sensitive to the flameholder fueling rate than was indicated in the measurements.
Hybrid Reynolds-Averaged/Large-Eddy Simulation of a Scramjet Cavity Flameholder
AIAA Journal ; 55 , 2 ; 544-560
2016-12-21
17 pages
Article (Journal)
Electronic Resource
English
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