Basic Study on coolability of Superconducting Magnet with Helium II

作为超流氦II冷却超导磁体线圈的基础研究，对封闭端加热、另一端恒温的Gorter-Mellink管道内的相互对流换热进行了数值研究。采用双流体模型，引入G-M互摩擦项，以考虑正常流体和超流流体之间的相互作用。得到了阶梯加热和斜坡加热两种加热方式下的瞬态结果。计算结果与货车Sciver的实验结果基本一致。基于双流体模型，编制了计算程序，分析了氦Ⅱ超流流动的稳态传热。数值计算结果与文献中的实验数据吻合较好。将两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解释，验证了简化模型的正确性。并对简化模型进行了瞬态分析。

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.