Published By: Blue Eyes Intelligence Engineering

Abstract — The proposal of supersonic combustion has become inevitable to fly at hypersonic speeds, but the problem of efficient mixing, flame holding and flame stabilization in supersonic combustors is yet to be overcome. Cavity based flame holders, which was used in subsonic combustors earlier is now extensively studied as supersonic combustor flame holders. The mixing characteristics of supersonic cavity flame holders depend on the formation of subsonic recirculation zone inside it. In this paper, open and closed single cavities with and without aft wall angle are analyzed to find out the optimum cavity configuration among them. The geometry was designed in ANSYS Design Modeler and the numerical analysis was done in ANSYS FLUENT 13.0 using the two dimensional density based energy equation and the turbulent characteristics are modeled using standard k-ε turbulence model. The contours of static pressure, static temperature, turbulence kinetic energy, total pressure and x-velocity were taken along the model length for comparison. From the results obtained, it is observed that cavity with L/D=10 and 45 ° aft wall angle showed better performance in terms of mixing characteristics and flame holding capability with no significant increase in total pressure loss compared to the other models. Single cavities with L/D=10 as well as cavities with aft wall angle showed better performance compared to single cavities with L/D=5 and with no aft wall angle respectively. Index Terms — aft wall angle, supersonic combustion, single cavity, turbulence kinetic energy I