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本文以大口径多屏绝热金属液氦实验杜瓦为研究对象,对之进行了热分析,导出了颈管温度场分布的微分方程。利用数值方法解出了不同蒸发速率下对应的颈管温度场分布,并讨论了多屏屏位的确定方法,在瓶塞与杜瓦材料、结构及尺寸一定的条件下,采用经验式及一些假设,我们求出了理论最小屏数及对应屏位和实际最小屏数及对应屏位,由此计算结果分析了影响多屏绝热绝热性能的主要因素。对瓶塞长度的优化设计我们也进行了讨论。另外文中示出了由最小二乘法获得的一些金属材料热导率及辐射率随温度变化的关系式和氦蒸汽定压比热随温度变化的关系式,这些关系式对杜瓦的规范化设计是必不可少的。采用本文所提供的计算方法可进行多屏绝热金属液氦杜瓦的规范化设计。
In this paper, large-diameter multi-screen adiabatic metal liquid helium experiment Dewar was studied, and the thermal analysis was carried out. The differential equation of the temperature distribution of the neck tube was deduced. The corresponding temperature distribution of neck tube under different evaporation rates was solved numerically. The method of determining the multi-screen screen position was discussed. Under the conditions of certain structure and size of the bottle stopper and Dewar, empirical and some Assuming that we have calculated the theoretical minimum screen size and the corresponding screen position and the actual minimum screen size and the corresponding screen position, the calculation results analyzed the main factors that affect the multi-screen adiabatic performance. We also discussed the optimal design of the length of the stopper. In addition, the article shows the thermal conductivity and emissivity of some metal materials obtained by the least squares method, and the relationship between the specific heat of constant pressure and the constant temperature of helium vapor, the relationship between these formulas for the design of Dewar is necessary. The calculation method provided in this paper can be used to standardize the design of multi-screen thermal insulation liquid helium Dewar.