Study on coupled heat transfer of pyrolytic kerosene and supercritical CO2 in zigzag-type PCHE used for hypersonic vehicle power generation system

Abstract

Supercritical CO2 closed cycle is an effective solution to the power generation challenge of hypersonic vehicles. The coupled heat transfer between aviation kerosene and supercritical CO2 within the zigzag-type printed circuit heat exchanger (PCHE) is the core thermal process of the whole cycle. Starting from the enhancement of the cycle's power generation, this study analyzes the influence mechanism of structural parameters on the heat transfer process through numerical simulation. The research indicates that a deep pyrolysis reaction of aviation kerosene, with the chemical heat absorption rate accounting for over 65 % of the total heat transfer rate. Due to the significant nonlinearity introduced by pyrolysis, traditional enhanced heat transfer design methods may even weaken its heat exchange. Unlike most studies, this type of PCEH achieves optimal heat transfer performance with a larger channel diameter and a smaller bend angle. Additionally, the increase in diameter and the decrease in bend angle enhance the power capacity of kerosene and its pyrolysis products, significantly improving the efficiency of thermal-electric conversion for the cycle. Finally, the study has determined a diameter of 2.4 mm and a bend angle of 30° constitute a set of structural parameters most suitable for the PCHE.