Effective thermal conductivity (ETC) is an important parameter for thermal analysis of superconducting coils. In this paper, the analytical expression of the ETC of the adiabatic and closely compacted superconducting magnet is given, which provides a convenient and accurate method for calculating this parameter. Based on the thermal resistance model, a unit cell of coil is selected as the research object to educe the expression. The calculated results are in good agreement with the experimental data in the literature, which shows the rationality of the analytical expression. This paper further discuss about the effects of some factors on ETC. The results suggest that the thermal conductivity of insulation has a linear effect on the radial and axial ETC, while the specific residual resistivity ratio (RRR) of the copper matrix is positively correlated with the circumferential ETC. The circumferential ETC increases rapidly with the increase of the Cu-to-NbTi ratio (Cu/NbTi). However, when Cu / NbTi ratio is greater than 10, the increase of circumferential ETC is very small.

有效热导率（ETC）是超导线圈热分析的重要参数。本文给出了绝热密实超导磁体ETC的解析表达式，为该参数的计算提供了一种方便、准确的方法。在热阻模型的基础上，选取线圈的一个单胞作为研究对象，推导出表达式。计算结果与文献中的实验数据吻合较好，说明了解析表达式的合理性。本文进一步讨论了一些因素对ETC的影响。结果表明，绝缘材料的热导率对径向和轴向 ETC 具有线性影响，而铜基体的比残余电阻率（RRR）与圆周ETC呈正相关。圆周 ETC 随着 Cu 与 NbTi 比 (Cu/NbTi) 的增加而迅速增加。然而，当Cu/NbTi比大于10时，周向ETC的增加很小。