A thermal performance factor for evaluation of active engine cooling with asymmetric heating

A theoretical expression of thermal performance factor has been derived in this paper for simple engineering evaluation of different cooling channel designs with asymmetric heating, intended for regenerative engine cooling applications in the aerospace propulsion and power-generation systems. As a specific example, numerical study has been conducted for conjugate heat transfer of the cryogenic methane in rectangular engine cooling channels at a supercritical pressure, with a constant heat flux enforced on the top channel wall. The thermal performance factor is used for practical assessment of the various engine cooling channel designs, in terms of both heat transfer enhancement and pressure loss. Results show that the geometric parameters of the cooling channel, in addition to the Nusselt number and friction factor, play a crucial role in determining the overall performance of fluid flows and heat transfer. An optimum cooling channel design could be approximated using the thermal performance factor as a first-step engineering design tool.