Ignition and combustion characteristics of supersonic combustor under flight Mach number 2.6–3.8

Abstract

This paper simulated the flying conditions of flight Mach number 2.6 ~ 3.8. Under the inflow state of the total temperature of 507 K ~ 820 K, the ignition test under low total temperature was carried out on the supersonic combustor by using the hydrogen-guided flame ignition method. When the total temperature was 820 K (simulated flight Ma = 3.8), the kerosene sprayed by the non-strut spray block could achieve a single stable combustion after removing the Pioneer hydrogen, and the fuel rich limit of the combustor was 0.4. When the total temperature was 700 K (simulated flight Ma = 3.4), when the non-strut spray block was used, the kerosene after removing Pioneer hydrogen could not be burned stably alone. In the test with blocking ratios of 20% and 10%, kerosene could be burned steadily alone, but the combustion-induced back pressure propagated upstream to the entrance of the isolator, destroying the inlet flow conditions. When the spray block with blocking ratio of 7.3% and 5% was used for the test, kerosene could be burned stably alone, and the incoming flow conditions were not destroyed. At a total temperature of 600 K (simulated flight Ma = 3.0) and 507 K (simulated flight Ma = 2.6), hydrogen and kerosene with a blocking ratio of 7.3% were used to achieve stable combustion, but the combustion-induced back pressure severely damaged the inlet flow conditions of the combustor. After the Pioneer hydrogen was removed, kerosene at both total temperature conditions could not be burned steadily. This study extended the lower limit of the working Mach number of the ramjet engine, and provided a reference flame stabilization method and fuel injection scheme for the kerosene combustion of the supersonic combustor, and provided some design suggestions for the low-Mach-Number combustor.