A comprehensive review of the thermal cracking stability of endothermic hydrocarbon fuels

In the current design of hypersonic vehicle, endothermic hydrocarbon fuel (EHF), as a combustible coolant, can not only solve the thermal management problem of the engine, but also provide sufficient propulsion for the vehicle. Importantly, when the fuel passes through the cooling channel of the engine as a coolant, it will absorb excess heat through a thermal cracking chemical reaction, but the deposits formed during the heat exchange process will directly affect the operation safety of the vehicle. Therefore, the stability of thermal cracking is one of the key issues of endothermic hydrocarbon fuels. This paper reviews the research progress on the thermal cracking stability of endothermic hydrocarbon fuels, and introduces the thermal cracking mechanism of endothermic hydrocarbon fuels under thermal stress and the corresponding reaction dynamics. After that, different evaluation techniques (thermal cracking and deposition), as well as factors (physical and chemical factors) that affect the stability of thermal cracking of endothermic hydrocarbon fuels, were analyzed. Finally, the corresponding improvement methods for improving fuel heat sink and reducing deposition are summarized. This will help to design endothermic hydrocarbon fuels with high thermal cracking stability and further develop high-performance vehicle.