车载、船载及机载氢能动力系统对高效紧凑型液氢气化装备需求迫切。印刷电路板式换热器（PCHE）凭借结构紧凑、耐低温等优势可满足移动载具的空间约束与动态响应要求，但其内部液氢流动沸腾过程中相态演化规律与传热特性尚不明确，无法为紧凑式液氢气化器的设计优化提供依据。为此，本文建立了双通道逆流PCHE三维流动沸腾换热模型，数值研究了深低温工况下液氢流动沸腾传热特性。液氢入口温度为20 K，出口压力为1 MPa。加热介质乙二醇入口温度为330 K，出口压力为0.5 MPa。结果表明，液氢在极短的距离内迅速气化，进入核态沸腾阶段，入口段局部换热系数较高，湍动能显著升高；随后进入膜态沸腾阶段，局部换热系数大幅减小。在液氢完成气化后逐渐升温过程中努塞尔数（Nu）沿程增大而摩擦因子（f）沿程减小。当液氢入口质量流量由5.98×10-6 kg/s增大至1.79×10-5?kg/s，换热效率增强，但压降显著增大，平均Nu增大12.9%~107.4%，平均f减小7.9%~19.6%。当乙二醇入口质量流量由9.33×10-4 kg/s增大至2.8×10-3 kg/s时，平均Nu数增大13.6%~79.2%，平均f减小2.4%~10.4%。研究结果为氢能动力系统小型相变换热器的流道设计与运行参数优化提供依据。

Vehicle-mounted, shipborne, and airborne hydrogen energy power systems have an urgent demand for efficient and compact liquid hydrogen vaporization equipment. Printed Circuit Heat Exchangers (PCHE) can meet the space constraints and dynamic response requirements of mobile vehicles by virtue of their compact structure, cryogenic resistance and other advantages, but the phase evolution law and heat transfer characteristics during the flow boiling process of liquid hydrogen inside them are still unclear, which cannot provide a basis for the design and optimization of compact liquid hydrogen vaporizers. Therefore, this paper establishes a three-dimensional flow boiling heat transfer model of a dual-channel counter-flow PCHE to numerically study the heat transfer characteristics of liquid hydrogen flow boiling under deep cryogenic conditions. The inlet temperature of liquid hydrogen is 20 K and the outlet pressure is 1 MPa. The inlet temperature of the heating medium ethylene glycol is 330 K and the outlet pressure is 0.5 MPa. The results show that liquid hydrogen rapidly vaporizes within an extremely short distance and enters the nucleate boiling stage, with a high local heat transfer coefficient and a significant increase in turbulent kinetic energy in the inlet section; subsequently, it enters the film boiling stage, and the local heat transfer coefficient decreases sharply. During the gradual temperature rise after the complete vaporization of liquid hydrogen, the Nusselt number (Nu) increases along the flow direction, while the friction factor (f) decreases. When the inlet mass flow rate of liquid hydrogen increases from 5.98×10?? kg/s to 1.79×10?? kg/s, the heat transfer efficiency is enhanced but the pressure drop increases significantly, with the average Nu increasing by 12.9%~107.4% and the average f decreasing by 7.9%~19.6%. When the inlet mass flow rate of ethylene glycol increases from 9.3×10-4 kg/s to 2.8×10-3 kg/s, the average Nu increases by 13.6%~79.2% and the average f decreases by 2.4%~10.4%. The research results provide a basis for the flow channel design and operating parameter optimization of compact phase-change heat exchangers in hydrogen energy power systems.

海南省科技专项；海南省自然科学基金