Flow distribution of supercritical hydrocarbon fuel in parallel regenerative cooling channels under non-uniform heat flux

Abstract Regenerative cooling technology is an important approach for thermal protection in scramjet engines. Non-uniform axial and circumferential heat flow distribution on the combustor leads to improper flow distribution, resulting in reduced cooling efficiency and localized overheating, potentially causing thermal protection failure. To effectively utilize the fuel heat sink and enhance cooling efficiency, it is necessary to investigate the mechanism of flow distribution in the channels under different heat flow conditions. This study investigates the flow and heat transfer characteristics in single cooling and parallel channels under various heat flux. The heat transfer characteristics, flow resistance changes, and the influence of heat flux on heat transfer deterioration are analyzed. There are two types of heat transfer deterioration in channels, caused by the inlet effect and the mutation of fuel supercritical properties. Furthermore, the mechanism behind flow deviation induced by non-uniform heat flux in parallel channels is investigated. When a supercritical process occurs, non-uniform heat flux induces temperature deviations, resulting in density distribution variations. This, in turn, influences velocity distribution and leads to disparities in flow resistance distribution. Consequently, flow deviation occurs, and the cracking reaction amplifies flow deviation while reducing temperature deviation.