Integration of $\hbox{LN}_{2}$ Multiphase Heat Transfer Into Thermal Networks for High Current Components

Abstract

Superconducting devices operating at liquid nitrogen LN2 temperature are increasingly used in power engineering. This paper describes a method to calculate the spatial distribution of temperature rise due to high current densities in electrical joints, which result in excessive transient and steady state heat generation. In order to compute heat conduction between and along adjacent solid domains, a thermal network method using analogies between thermal and electrical network is convenient. Sufficiently simple correlations for convective heat transfer coefficients are required. The given calculative approaches and principles were selected, evaluated and integrated into a thermal model. This model was approved by experimental investigations using high currents and transient cooling processes and implemented into PSpice simulation software.