Performance analysis of a thermal management system based on hydrocarbon-fuel regenerative cooling technology for scramjets

Thermal protection and power generation are two of the major technical challenges in developing hypersonic vehicles with long-range/endurance. This research is aimed to provide a system for thermal protection and power generation for hydrocarbon-fueled scramjets. This study proposed a thermal management system based on fuel vapor turbine (FVT) and closed-Brayton-cycle (CBC) to generate power, and a bypass loop is connected with CBC in parallel to ensure thermal protection demand. A performance analysis model considering the combustor and cooling channels is established. The combustion and heat transfer process are described in a quasi-one-dimensional way, while FVT and CBC are described in a zero-dimensional form. Results indicate that large CBC power generation efficiency (η_PG,CBC) and FVT expansion ratio (π_FVT) can improve power generation with the same thermal protection performance. Because of the integrated variation law of cooling heat exchange and η_PG,CBC, there exists an optimal value of fuel outlet temperature (T_f3) while meeting the thermal protection requirement. The high Mach number and low equivalence ratio both require a significant increase in the cooling capability of fuel, and it is feasible to sacrifice the power generation of the CBC subsystem to meet the thermal protection demand.