Enhancing mixing features in supersonic flow through geometric correction of the cavity depth relative to the height of the combustion chamber

Abstract

The conventional method for cavity analysis is solving two-dimensional equations. The two-dimensional implicit and densitybased Reynolds averaged Navier-Stokes equations and the two-equation standard k-ε turbulence model have been employed to numerically simulate the cold flow field in a single-cavity flame-holding configuration of a supersonic combustor. The cross section of the combustor is assumed to be rectangular. The supersonic inlet is supposed for the steady and unsteady flow conditions along with normal directions to the inlet. For the validation purpose, the numerical results are compared with those of the experimental data available in the current literature. It is quite well-known that the cavity in supersonic combustors helps to separate the fuel from the wall configuration while improving the mixing process in supersonic flows. However, the selection of the most efficient depth for the cavity is crucial in obtaining optimum conditions. In the present research work, the role of the cavity length-to-height (L/D) ratio, the channel height-to-cavity height (H/D) ratio and Mach number are studied numerically. The obtained results indicate that the wall static pressure profiles of validation case predicted by the numerical approaches are well in agreement with those of the experimental data. Also, H/D = 2 was found to be the best choice for the combustion chamber height relative to the cavity depth. The designed geometry is modeled in a commercial software using two-dimensional density-based energy equations while the turbulent characteristics are modeled using standard k-ε turbulence model.