Influence of equivalence ratio on characteristics of continuously rotating detonation combustor

Based on two-dimensional compressible Euler equation, a series of numerical studies were conducted to investigate the effect of equivalence ratio on continuously rotating detonation combustor (CRDC) using methane-air mixture. The developing process and lean-burn extinction process of detonation wave were researched, and the influence of inlet equivalence ratio on performance parameters was analyzed in detail. Results showed that, after ignition, two collisions happened in the developing progress of CRDC from the unstable state to the relatively stable state. Extinction happened in CRDC without happening of two collisions when the inlet equivalence ratio was too low. With the decrease of inlet equivalence ratio, the detonation wave propagation velocity, axial average velocity, outlet average temperature and outlet average total pressure all showed a downtrend. The fundamental reason for the downtrend of the pressurization ratio was that the decrease of entropy increase difference between the rotating detonation combustion process and the isobaric combustion process resulted in the decrease of the Gibbs free energy increment. The fuel residence time was at sub-millisecond level and the thermal efficiency was kept more than 99%.