中文摘要：

采用有限容积法和焓多孔介质模型数值模拟了组合式吸液芯内金属钠熔化的固液相变过程。由于液态金属钠和组合式吸液芯的导热系数在同一数量级，因而采用单温度模型，模拟过程中考虑了非达西效应影响和液态金属钠的自然对流现象。研究结果发现，组合式吸液芯中金属纤维毡厚度越小，金属钠受热熔化的速度越快，且熔化后的液态钠流速达到最大值所用的时间越短，进而可以缩短热管启动时间；组合式吸液芯中金属纤维毡厚度越大，竖直加热壁面的温度分布越均匀、壁面温差越小，进而减少了加热壁面产生过热点的可能。

英文摘要：

Based on the finite volume method and the enthalpy-porous model the solid-liquid phase change of sodium in the combined wick is numerically studied.The one-temperature model is used since the thermal conductivity of sodium is close to that of the combined wick materials.The non-Darcy law and natural convection in the melting process are taken into account.The results show that a thin metal fiber felt in the combined wick can result in a faster melting rate of the sodium and a shorter time for the molten sodium to reach the maximum velocity which can shorten the time for the high-temperature heat pipe startup.A thick metal fiber felt in the combined wick can result in a uniform temperature distribution in the vertical heating wall and a small wall temperature difference which can reduce the possibility of an overheat spot.