Control-oriented unsteady one-dimensional model for a hydrocarbon regeneratively-cooled scramjet engine

A control-oriented unsteady 1-D model for regeneratively-cooled scramjet engine which is composed of flow-combustion module, regenerative cooling module, is presented in this paper. It can reflect unsteady process in real-world where flow-combustion module couples with regenerative cooling module at each time step. The coupled 1-D model is quantitatively validated under steady and unsteady conditions. By the analyses of steady characteristics using this coupled 1-D model, it can be concluded that the allowable maximum first stage fuel equivalence ratio of regeneratively-cooled scramjet engine is lower and thrust is larger than no-cooled scramjet engine for the same equivalence ratio under the same flight Mach number. The difference of overtemperature boundary between regeneratively-cooled and no-cooled scramjet engine is also pointed. Moreover, regenerative cooling process results in moving toward less of fuel equivalence ratio of combustion mode transition. Unsteady characteristics analyses are investigated subsequently. Results indicate that there exists thermal inertia after kerosene flowing in cooling channels so that the flow rate of kerosene of entering into combustor cannot reflect kerosene changing signal in time. It leads to that thrust response time of regeneratively-cooled scramjet engine is longer than that of no-cooled scramjet engine. Some special attentions should be paid that combustion mode transition can be induced and affected by regenerative cooling process in some conditions. As a whole, the low computation cost makes this coupled 1-D model suitable for control system design and overall performance evaluation for regeneratively-cooled scramjet engine.