Numerical Study of Effect of Fuel Injection Angle on the Performance of a 2D Supersonic Cavity Combustor

Abstract

Direct injection into a cavity-based supersonic ramjet combustor has been recently considered to be an effective way of stabilizing the flame over a wide range of operating conditions. In the present study, two-dimensional (2D) supersonic combustor with direct fuel injection from the cavity floor with various fuel injection angles is simulated for both nonreacting and reacting conditions using Fluent software. The various complex flow features like upstream shocks, compression waves, and Mach reflection are formed in the flow field. Low velocity recirculation regions are observed in the cavity, which assists in flame holding. Heat release was observed to have significant effects on various flow structures formed both in the main stream and cavity regions. In nonreacting conditions, injection at 135° shows maximum pressure losses followed by injection angle of 120°. However, the 120° injection angle case exhibits better mixing over other cases. The present study indicates that any change in injection angle does not have any significant effect on the air entrainment. In reacting conditions, the 120° injection angle shows highest combustion efficiency because of better mixing properties exhibited by this location.