液氢用低温复合多层绝热材料的传热特性研究

Research on heat transfer characteristics of composite multi-layer insulation material under liquid hydrogen temperature range

基于液氢高效储运对低温绝热的需求,将液氢温区复合多层绝热材料(包含泡沫材料与多层绝热材料)作为研究对象,通过Layer-by-Layer模型构建复合多层绝热材料层间温度分布数值模型,分析了热通量随热边界温度、真空度与总层数变化规律。结果表明,热通量随着热边界温度的升高而增大,靠近冷边界区域的多层绝热材料承担了主要的绝热功能。随后对不同组合模式改变真空度下传热特性进行分析,发现相较于多层绝热材料,添加泡沫材料热通量减少20.76%。此外,复合多层绝热材料中多层绝热材料总层数的增加可以有效抑制热通量增加,综合考虑性能成本,在总层数为50层时抑制效果达到最佳,此时热通量为0.537 7 W/m^(2)。

The heat transfer characteristics of composite multilayer insulation materials used in the storage and transportation of liquid hydrogen at low temperatures were studied.The re-search focused on analyzing the effects of thermal boundary temperature,total number of layers,and vacuum degree on the heat flux of the insulation material.Based on the Layer-by-Layer mod-el,the heat transfer model of composite multilayer insulation materials was constructed.The re-sults indicate that the heat flux increases with higher thermal boundary temperatures,with the mul-tilayer insulation material near the cold boundary area playing a crucial role in insulation.Fur-thermore,numerical analysis was conducted to examine the impact of different combinations of ma-terials and changes in vacuum degree on heat transfer characteristics.The findings reveal that the addition of foam materials reduces the heat flux by 20.76% compared to multilayer insulation ma-terials alone.Additionally,increasing the total number of layers in the composite multilayer insu-lation material mitigates the growth of heat flux effectively.The optimal heat flux of 0.5377 W/m^(2) is achieved with a total of 50 layers.