Evaluation Model for Fast Convective Heat Transfer Characteristics of Thermal Cracked Hydrocarbon Fuel Regenerative Cooling Channel in Hydrocarbon-Fueled Scramjet

Abstract

• A fast flow and heat transfer evaluation model with simplified endothermic pyrolysis was established. • Influence of inlet fuel mass flow on flow and heat transfer characteristics was studied. • Influence of two types heat flux on flow and heat transfer characteristics was studied. • An inner fuel temperature inside cooling channel detective method was derived from above results. Regenerative cooling is critical for hypersonic propulsion systems, wherein the flow and heat transfer characteristics of the hydrocarbon fuel in the cooling channel are crucial. The most commonly used existing evaluation models for flow and heat transfer characteristics use one-step overall reaction endothermic pyrolysis; however, they are limited to mildly cracked hydrocarbon fuel working conditions. To quickly evaluate the flow and heat transfer characteristics of hydrocarbon fuel under both mild- and heavy-cracking conditions, a quasi-one-dimensional model was established in this study; considering 18 species and 24 reactions, and a simplified mechanism of n-decane. The flow and heat transfer characteristics under different cooling channel lengths and heat fluxes were studied. The results show that the proposed model has fast flow and heat transfer characteristics evaluation capability, and small persistent errors. Furthermore, the calculation results under different inlet fuel mass flow and heat flux working conditions showed that the hydrocarbon fuel flow and heat transfer characteristics vary with the fuel mass flow and heat flux, which can enhance both heat transfer and deterioration. The influence of the heat flux can be used to measure the fuel temperature inside the channel.