Effect of Subsonic Microjets on Reacting Flow in Dump Combustors

Abstract

In order to improve the efficiency and performance of air-breathing liquid-fuel combustors, advanced control strategies must be developed. The backward-facing step dump combustor is a conventional flame holder which causes flow separation after the step. Novel design concepts are necessary for controlling and manipulating the fluidic shear layer that develops inside these chambers. The dynamic mixing and burning that occurs within this design are key mechanisms for turbulent combustion. Because these systems carry a substantial drag penalty, control techniques are developed to create a compact, low drag combustor for high-speed propulsion applications. Microjets, which are traditionally used for noise reduction techniques in aerospace systems, are used in this work to generate higher turbulence and three-dimensionality within the turbulent reacting shear layer of a dump combustor. The focus of this work is to use numerical simulations to study the effects of microjets on the reacting flow-field for improving flame stabilization. The threedimensional simulations for turbulent combustion are conducted using the Reynoldsaveraged Navier-Stokes (RANS) method.