Helium Composite Regenerator

该第二阶段计划的目标是制造和测试新型低温复合材料，用于10K以下工作的闭式循环制冷机的回热器。该材料是一种自加载到金属扩展表面结构中的氦复合材料，其分散形式适合回热器的热通量和频率要求。3~6K的高有效热容来源于亚临界氦的汽化和凝结潜热，10K以下的高有效热容来源于加压氦的显热。再生器中的高各向异性导热系数源于金属部件的几何形状。高热容和高径向导热系数的组合允许快速热渗透和高再生器效率。在液氦温度下，利用不涉及焦耳-汤姆逊气体节流阶段的闭路循环制冷机，有可能实现相当大的制冷功率。

The object of this Phase II program is to fabricate and test novel cryogenic composites designed for use as regenerators in closed-cycle cryocoolers operating below 10 K. The material is a composite of helium self-loaded into a metallic extended surface structure whose dispersion form is suitable for the thermal flux and frequency requirements of regenerators. High effective heat capacity from 3 - 6 K derives from the latent heat of vaporization and condensation of subcritical helium, and high heat capacity below 10 K derives from the sensible heat capacity of pressurized helium. High, anisotropic thermal conductivity in the regenerator derives from the geometric form of the metallic component. The combination of high heat capacity and high radial thermal conductivity allows for rapid thermal penetration and high regenerator effectiveness. The potential exists to achieve significant refrigeration power at liquid helium temperatures with a closed-cycle cryocooler not involving a Joule-Thomson gas- Throttling stage.