Stability Analysis of Forced-Flow Cooled Superconductor

本文对超导复合材料在强流超临界氦冷却下的热稳定性进行了数值分析，考察了几个参数对热稳定性的影响。结果总结如下。1.当淬火发生时，氦气压力迅速上升，正常区向上游和下游方向传播。2.稳定极限随着初始流速和冷却剂通道直径的增加而增加，并且随着氦气温度和运输电流的减小而增加。3.当输流较小时，初流速对稳定极限的影响显著。4.在大输流条件下，瞬态换热比初始流速的影响要大得多。5.输运电流越大，氦初始温度对稳定极限的影响越大。6.冷却剂通道越大，氦气流速对稳定极限的影响越小。7.导体稳定性不依赖于本分析中所涵盖的初始压力（0.3-0.8[MPa]）。8.初始瞬态传热的影响很大，超导体是否失超主要取决于热扰动后10 ms左右。

A numerical analysis of the thermal stability of a superconductor composite cooled by forced-flow supercritical helium has been conducted and the influence of several parameters on the thermal stability examined. The results are summarized as follows. 1.When quenching occurs, the helium pressure rises rapidly and the normal zone propagates towards the up- and downstream directions. 2.The stability limit increases with an increase in the initial flow velocity and the diameter of the coolant passage, and with a decrease in the helium temperature and the transport current. 3.When transport current is small, the effect of initial flow velocity is remarkable on stability limit. 4.In the condition of large transport current, transient heat transfer has much larger effect than initial flow velocity. 5.The larger transport current is, the larger the effect of initial helium temperature is on stability limit. 6.The larger the coolant passage is, the less the effect of helium flow velocity is on stability limit. 7.The conductor stability does not depend on the initial pressure covered in the present analysis (0.3-0.8[MPa]). 8.The effect of initial transient heat transfer is very large, it is decided mostly within some 10 [ms] after heat disturbance whether superconductor quenches or not.