Numerical analysis of flow and heat transfer characteristics of supercritical endothermic hydrocarbon fuel in taper tube

To enhance the cooling performance of the scramjet regenerative cooling system, a novel taper tube is proposed. Under supercritical pressure, the flow characteristics and heat transfer characteristics of endothermic hydrocarbon fuel (EHF) in taper tube, narrow cylindrical tube, and wide cylindrical tube are numerical investigated and compared. The results of the investigation of flow and heat transfer processes in the above three tubes indicate that the taper tube effectively facilitates the pyrolysis of n-decane and the n-decane conversion is increased by 3.94%, compared with narrow cylindrical tube. Compared with wide cylindrical tube, the taper tube enhances cooling effect and the wall temperature near the outlet is reduced by 50.16 K. The taper tube contributes to the cooling structure optimization and promotion of regenerative cooling system performance.