Flow and thermal performance of supercritical n-decane in double-layer channels for regenerative cooling of a scramjet combustor

In order to improve the active regenerative cooling performance of a scramjet using supercritical n-decane, a new type of cooling channel, the double-layer channel, is proposed. Based on reliable numerical simulations, temperature profiles, fluid flow track, vortex structure and buoyancy force distribution of three cases are presented, respectively. It is found that the heat transfer performance of the double-layer channel with the same flow direction is better than the other cases and the heat transfer deterioration (HTD) phenomenon is effectively weakened and the wall temperature is greatly reduced. A cross-flow and a large vortex structure induced by the buoyancy forces are helpful to the occurrence of the HTD phenomenon. An “M” type temperature profile and an “M” type buoyancy force distribution are important characteristics of the HTD phenomenon.