Performances of Supersonic Model Combustors with Distributed Injection of Supercritical kerosene

Abstract

Supersonic model combustors with two-staged injections of supercritical kerosene were experimentally investigated in both Mach 2.5 and 3.0 facilities with the stagnation temperatures of approximately 1750K. Supercritical kerosene at temperatures of approximately 760K and various pressures was prepared using a two-staged heater developed in Ref. 1 and injected at equivalence ratios of 0.98 to 1.46. Two pairs of integrated injector/ flameholder cavity models in tandem were used to facilitate the fuel-air mixing and stabilize the combustion. Combustor performances with different fuel injection locations, injector numbers, combinations of injection stages, and combustor entry Mach numbers were investigated systematically and discussed based on the measured static pressure distributions and the specific thrust increments due to combustion. With two-staged fuel injections the overall performance of the combustors was shown to be improved and fuel injections at equivalence ratio higher than unity could be reached without combustor-inlet interaction. Reducing the number of injectors while increased its diameter was very effective to increase the pressure rise in the combustor with single-stage injections but had little effect on the combustor performance with two-staged fuel injections. Increasing the entry Mach number resulted in lower combustion levels, in particular, with fuel injections at locations close to the combustor exit but was balanced with two-staged fuel injections.