Thermodynamic performance analysis of the rotating detonative airbreathing combined cycle engine

Abstract

A configuration is presented for the rotating detonative airbreathing combined cycle engine with compatibility between the turbomachinery and rotating detonation combustor being realized. Two propulsion units are merged to achieve three different operating modes, which provides a favorable propulsion choice for advanced full range and trans-aerosphere vehicles. For the vehicle taking off from the ground, the engine operates at turbojet mode until the thrust demand could not be satisfied. Then the ramjet unit ignites and the operating mode turns into transition mode, during which the ratio of the thrust generated by ramjet unit to the total thrust increases with an increase in Ma0. When the ratio reaches 1.0, the engine transforms into the ramjet mode. Thereafter, a mode transition strategy with the thrust and freestream mass flowrate remaining constant is proposed for the combined cycle engine, based on the steady state characteristics of turbine and ramjet units. Furthermore, the parametric performance simulation model of the engine is developed to verify the potential performance improvements generated by the application of rotating detonation technology, and analyze the application characteristics of the mode transition strategy formulated in this study. It is shown the lower initial Mach numbers of mode transition result in higher values of equivalent specific thrust but lower values of equivalent specific impulse during the transition mode. For the detonative combined cycle engine, the minimum value of initial Mach number of mode transition is below 2.0, which is much lower than that of the conventional turbine based combined cycle engine. Therefore, the performance during transition mode is expected to be improved with the application of rotating detonation technology.