Study on the temperature distribution of long length HTS power cable cooled by circulating slush nitrogen

Abstract

A numerical model to calculate the temperature distribution of 3 km long high temperature superconducting (HTS) power cable is established. The model assumes that HTS power cable is cooled by circulating nitrogen. The model considers mass, momentum, and energy balance of the nitrogen, and the heat diffusion inside the HTS layer. The result of the numerical model shows that the maximum temperature of HTS layer is higher than 80 K when the HTS cable is cooled by the compressed liquid nitrogen. Since the result shows that the minimum enthalpy of the compressed liquid nitrogen is not sufficiently small to cool the HTS cable below 80 K, the slush nitrogen is introduced to achieve lower maximum temperature of the HTS layer. Changing the volumetric fraction of the solid nitrogen, the maximum temperature of the HTS layer is calculated. The maximum temperature of the HTS layer decreases about 6.7 K when the slush nitrogen with 30% of solid nitrogen is supplied instead of the liquid nitrogen. The result of the numerical analysis and the discussion are presented.