Analytical Modeling of Unsteady Heat Transfer in Rotating Detonation Engines

An unsteady heat transfer model is proposed for quantifying heat flux and wall temperature profiles in a rotating detonation combustion environment. This work investigates the heat flux trends in rotating detonation combustors to provide higher accuracy than traditional rocket correlations and developed via first principles. It is demonstrated that a one-dimensional analysis is appropriate for describing the effective heat flux and wall temperature profile; this is due to the disparity in length and time scales between thermal diffusion and the wave arrival. Specifically, wall temperature fluctuations are ��(10 K) or less when heat flux amplitudes are below 10 MW/m² and operating frequencies above 10 kHz for typical combustor materials (e.g., GRCop-42, GRX-810, Inconel 718, silicon carbide). Additionally, as it is shown that fluctuations in wall temperatures are 2-3 orders of magnitude lower than the freestream values, isothermal walls provide excellent approximations for modeling the heat flux at realistic chamber conditions. This work therefore provides a framework for improved thermal characterization within the near-detonation region; this will help work towards the development of thermal management strategies capable of meeting the increased heat flux requirements for detonation-based combustion devices.