An experimental investigation of combustion modulation techniques for a solid fuel ramjet

Abstract

An experimental investigation was conducted to examine the effects of inlet air swirl and secondary gas injection on the combustion properties in a solid fuel ram jet. Tests were conducted with both HTPB and PMM fuels in order to obtain general results. The swirl tests were conducted at high and low air mass fluxes with equivalence ratios less than unity. Swirl was found effective for increasing the fuel regression rate but the magnitude was highly dependent upon motor geometry, fuel type and operating environment. The gas injection tests included hydrogen at low equivalence ratios, and nitric oxide and nitrous oxide at high equivalence ratios. Secondary injection generally resulted in increases in combustion pressure in agreement with equilibrium, adiabatic combustion expectations.