Experimental study of average and high-frequency wall heat flux characteristics in a compact rotating detonation engine

This study investigates the wall heat flux characteristics of rotating detonation combustors, which exhibit unique thermal behaviors distinct from traditional deflagration-based combustion chambers. A series of experimental tests on a compact rotating detonation engine were designed and implemented, utilizing methane/GOX as propellants. High-frequency heat flux measurements were conducted to analyze instantaneous and average heat flux distributions, as well as heat flux distortion characteristics. The effects of mass flow rate and equivalence ratio on heat flux were systematically examined, and three dimensionless parameters were introduced to quantify thermal load fluctuations. The key findings show that the combustor walls experience high-frequency periodic thermal loads, with frequencies consistent with those of the rotating detonation waves. At a constant mass flow rate, both the average heat fluxes in the detonation region and the global heat flux initially rise and then decline with increasing equivalence ratios, reaching maximum values within the range of 1.2–1.3. The heat flux fluctuation intensity is highest in the detonation region, typically ranging between 1.5 and 2.5. The circumferential distortion intensity remains stable at 4%–6% under stable detonation modes. The axial distortion intensity remains within 40%–50% for equivalence ratios below 1 but increases rapidly for equivalence ratios above 1, likely due to the competitive interaction between detonation and deflagration. These results provide critical insights for the thermal protection design of RDCs and advance the engineering application of RDEs.