中文摘要：

以发动机主动再生冷却系统为研究对象,建立了碳氢燃料热物性高精度计算方法,在此基础上对超临界压力下低温甲烷在水平波纹管内的流动换热现象展开数值研究,初步分析了波纹管强化换热机理。进一步系统研究了波纹管节高比、管壁材料导热系数、壁面热流密度、入口压力以及雷诺数对强化换热和阻力特性的影响,并采用综合换热性能评价准则对各种因素的影响进行评价。研究表明：在超临界压力下合理选择波纹管可以显著提升换热能力,消除传热恶化现象,并且不会带来明显的压降损失;存在一个最优波高和最佳雷诺数,使波纹管具有最优的综合换热性能;增大管壁材料导热系数和甲烷入口压力可提高换热能力。

英文摘要：

The active regenerative cooling system of the rocket engine is studied, and a method is developed to give an ac- curate estimation of thermophysical properties. A numerical investigation of convective heat transfer of cryogenic-propellant methane in horizontal corrugated tubes at supercritical pressures is conducted. The heat transfer enhancement mechanism of corrugated tubes is analyzed, The effects of several key influential parameters on both heat transfer enhancement and pres- sure drop are investigated, including the pitch-to-height ratio, wall thermal conductivity, wall heat flux, inlet pressure, and Reynolds number. The performance evaluation criteria are adopted to evaluate the thermal performance influenced by these parameters. Results reveal that reasonable corrugated tubes can significantly improve the heat transfer ability without cau- sing significant pressure drop at supercritical pressures, which is beneficial to the elimination of heat transfer deterioration. There exist an optimum corrugation height and Reynolds number for achieving the best overall thermal performance. Increase of wall thermal conductivity and inlet pressure can improve the heat transfer ability.