Experimental investigation on heat sink distribution of regenerative cooling with supercritical n-decane catalytic steam reforming

Thermal cracking of hydrocarbon fuels serves as a thermal management method for hypersonic vehicles, yet it faces challenges of insufficient cooling capacity and pyrolytic coking at high Mach numbers (Ma > 7). The steam reforming of hydrocarbon fuels is effective in improving heat sink and inhibiting coke formation. This study experimentally explores the effects of water content, mass flow rate, and pressure on heat sink distribution in different temperatures, with gaseous yield analysis revealing the mechanistic effects of steam reforming reactions in heat sink enhancement. The results indicate that the initial temperature of steam reforming reaction (360 ℃) is considerably lower than the temperature for thermal cracking reaction (490 ℃), implying an earlier release of the chemical heat sink. The higher water-content exhibits higher total heat sink in the low-temperature stage. In the high-temperature stage, the reaction path and carbon molar yield are affected by the various water contents, and the high water-content promotes the steam reforming reaction and reduces the production of coking precursor olefins. The mass flow rate primarily affects carbon molar yield by modifying reaction duration, while exerting negligible influence on the reaction pathways. High-pressure conditions accelerate the frequency of intermolecular collisions thereby facilitating the release of chemical heat sinks. This study is expected to provide both experimental data and theoretical guidance for the application of steam reforming in cooling channels of scramjet.