Study on influencing factors of combustion mode transition boundary for a scramjet engine based on one-dimensional model

Combustion mode transition is an important way for a dual-mode scramjet engine to obtain the high engine performance in a wide operating range of flight Mach number. In this study, the influencing factors on the combustion mode transition boundary for the scramjet engine was investigated based on a one-dimensional model proposed earlier by the authors. The definition of the combustion mode transition boundary was described. The effect of the duct area profile of the combustor, the heat release distribution in the combustor, the wall temperature and wall roughness of the combustor and the air composition of the incoming flow on the combustion mode transition boundary were analyzed. The result showed that the variation of these factors will make the combustion mode transition boundary deviate from the design value. The influencing rules found in this study will provide some theoretical foundations for designing the engine structure and the combustion mode transition control scheme of the scramjet engine. (C) 2019 Elsevier Masson SAS. All rights reserved.