Combustion Tests of a Staged Supersonic Combustor with a Strut

Abstract

To avoid combustor ‐inlet interaction,a staged supersoniccombustorwitha strutforthee rst-stageinjection and second-stage wall injectors at its divergent section was introduced to increase the pressure in the divergent section under the limitation of the peak pressure at its minimum cross-sectional area section. The combustor was tested experimentally in a direct-connect wind-tunnel facility with a combustion heater that supplied Mach 2.5 aire ow witha total temperatureof1500 K.With thestaged injections,thepressurerisedueto thesecond-stagecombustion was isolated from that due to the e rst-stage combustion. Fuel with an equivalence ratio more than unity, twice that of the allowable e ow rate with the e rst-stage injection alone, could be injected without the interaction, and the maximum thrust increment was augmented by 100%. The effects of thesecond-stageinjector placements were also examined, and it was found that the second-stage injection farther upstream resulted in the interaction, but that the injection further downstream resulted in low thrust due to low combustion efe ciency. Nomenclature A = cross-sectional area of e ow pass dF = thrust increment dIsp = specie c impulse based on thrust increment F = thrust P = pressure P.X/ = measured wall pressure at X, mm T = temperature X = streamwise location from step Y = spanwise location from duct center Z = lateral location from duct center ° = specie c heat ratio = Crocco factor (see Ref. 10) A = equivalence ratio Subscripts i = combustor inlet o = combustor outlet 0 = stagnant condition 1 = e rst stage 2 = second stage