Basic Study on coolability of Superconducting Magnet with Helium II

作为超流氦冷却超导磁体线圈的基础性研究，对封闭端加热，另一端恒温的Gorter-Mellink通道内的对流换热进行了数值研究。采用双流体模型，引入G-M相互摩擦项，考虑了正常流体和超流体之间的相互作用。给出了阶梯加热和阶梯加热两种加热方式下的暂态结果。计算结果与Van Sciver的实验结果基本一致。基于双流体模型的计算程序也被用来分析超流氦II流动的稳态换热。内对流换热和温度分布的数值计算结果与文献中的实验数据吻合较好。将双流体模型与简化模型进行了比较，并从数学角度对简化模型进行了验证。并用简化模型进行了暂态分析。

As a fundamental research on the cooling of superconductor magnet coil using superfluid helium II,numerical study is carried out on mutual convection heat transfer in a Gorter-Mellink duct heated at the closed end and kept at constant temperature at the other end that is open to a helium bath. Two-fluid model is adopted with the G-M mutual friction term to cover the interaction between the normal and the superfluid components. The transient results are obtained for two types of heating conditions : one is stepwise heating and the other rampwise heating. The obtained results generally agree with the experimental observations by Van Sciver.Computer code based on the two-fluid model is also developed to analyze steady state heat transfer of superfluid helium II flow. Numerical results for temperature profile and heat transport by internal convection are in good agreement with experimental data in literatures. Comparisons are made between the two-fluid model and the simplified model ; explanation from the mathematical point of view is provided to validate the latter. Transient analysis with the simplified model is also conducted.