针对低温液体火箭发动机预冷自然循环回路的流动与传热过程,建立了一维非稳态均相流数学模型,采用反环状流和弥散流两种流型描述膜态沸腾流型及传热特性.数值计算结果表明:自然循环预冷回路中推进剂流量的不稳定特性是由驱动力——循环回路释热量的不稳定性造成的;预冷过程约80%的管路壁面温度下降由膜态沸腾所引起;反环状流和弥散流膜态沸腾流型的引入,可较好解释回流管壁面温度在预冷过程中的逆向分布规律. Aiming at the flow and heat transfer process of precooling natural circulation circuit of cryogenic liquid propellant rocket engine, a one-dimensional mathematical model of unsteady flow is established. The flow pattern of membrane boiling and convection Thermal characteristics The numerical results show that the instability of the propellant flow in the natural circulation pre-cooling loop is caused by the instability of the heat release of the driving force-circulation loop, and the temperature of the pipe wall surface is about 80% Which is caused by the film boiling. The introduction of the bubbling flow patterns in the anti-cyclic flow and the diffusive flow can better explain the reverse distribution of the wall temperature in the pre-cooling process.