It is a challenging task to investigate the regenerative cooling of the variable thrust LOX/LCH4 expander cycle rocket engine. The decreasing methane mass flow rate leads to the two-phase instability in the regenerative cooling channels (RCC) for low engine thrust. In this study, the geometric dimension of RCC with phase-change is developed. Heat transfer cases are studied based on the experimental correlation, which are investigated the heat transfer characteristics of subcritical methane in the RCC. Furthermore, the effect of variable engine thrust on RCC's heat transfer characteristics is analyzed particularly for low engine thrust. The results demonstrate that the gas-side wall temperature ($T_{\text{wg}}$) was stratified due to the different phase-change heat transfer mechanisms. $T_{\text{wg}}$ appeared as a local peak value at the throat, which reached a maximum value in the two-phase region. The maximum value of $T_{\text{wg}}$ increased from 858.5 K to 863 K with the decrease of the engine thrust in 20–60% RPL. The RCC's temperature rise of 20% RPL was 1.25 times that of 60% RPL (231 K), whereas the pressure drop was 0.72 that of 60% RPL (0.73 MPa). Moreover, the case calculation results could benefit the scheme design and heat transfer analysis of the RCC.

研究变推力 LOX/LCH4 膨胀循环火箭发动机的再生冷却是一项具有挑战性的任务。降低的甲烷质量流量导致再生冷却通道 (RCC) 中的两相不稳定，以实现低发动机推力。在这项研究中，开发了具有相变的 RCC 的几何尺寸。基于实验相关性研究了传热案例，研究了RCC中亚临界甲烷的传热特性。此外，还分析了可变发动机推力对 RCC 传热特性的影响，特别是对于低发动机推力。结果表明，气体侧壁温度 (${吨}_{\text{工作组}}$) 由于不同的相变传热机制而分层。 ${吨}_{\text{工作组}}$在喉部出现局部峰值，在两相区达到最大值。的最大值${吨}_{\text{工作组}}$随着发动机推力的降低，RPL 从 858.5 K 增加到 863 K。RCC 20% RPL 的温升是60% RPL (231 K) 的1.25 倍，而压降是60% RPL (0.73 MPa) 的0.72。此外，案例计算结果有助于碾压混凝土的方案设计和传热分析。