中文摘要：

以低温绝缘型高温超导直流电缆的典型结构为基础，建立了制冷系统的水力一热力数学物理模型，用解析法分析计算了逆流和顺流两种基本制冷方式及其变种的制冷特性，分析了流量和绝缘层热导率对制冷特性以及最大制冷长度的影响．结果表明流量影响制冷系统的温度分布特性，在一定范围内，最大制冷长度随流量增大而增大；超过临界点，增大流量反而会缩短制冷长度．发现低温绝缘材料的热导率影响系统温度分布，且同等流量下使用低热导率绝缘材料有更长的制冷距离．本文的结果与结论对长距离应用的高温超导直流电缆系统的制冷站配置有参考意义．

英文摘要：

Typical structure of cold dielectric HTS DC cable was employed to establish the hydro-thermodynamic model. Analytical method was used to explore the cryogenic features of the basic types and their variations of count- er-flow and parallel-flow. The influences of flow rate of cryogen and thermal conductivity of dielectric material on cryogenic characteristics and accessible maximum cooling length were studied then. The results show that in a cer- tain range higher flow rate leads to longer cooling length, while higher rate shortens the cooling length when it sur- passes the critical point and thermal conductivity of dielectric material affects the temperature distribution and smal- ler thermal conductivity leads to longer cooling length. The results presented have reference significance for configu- ration of long distance HTS DC cable system.