Influence of flow rate and heat flux on the temperature distribution in long length counter flow cooled cold dielectric HTS cables

Abstract

The technical advantages of using High Temperature Superconducting (HTS) cables have drawn the attention of most of the researchers around the world. However, the cooling design of these cables nevertheless remains a challenge for the researchers and manufacturers. Therefore, in the present work, an attempt has been made to ease the challenge of cooling of long length High Temperature Superconducting (HTS) cables. Counter flow cooling arrangements of liquid nitrogen (LN2) have been proposed and analysed the longitudinal temperature distribution along the superconducting cable using heat balance equations. Also, in the present work the solution for the temperature distribution profiles of LN2 in counter cooled HTS cable are also obtained assuming one dimensional (1-D) model. In particular, nonlinear axial temperature profiles of LN2 in the counter cooled HTS cable are found. The single phase cold dielectric HTS cable with stainless steel corrugated pipes as flow paths are used for the analysis. Liquid nitrogen with varying volumetric flow rates of 20–35 L/min and total heat loss (A.C. loss and exterior heat load) of 2.3–2.6 W/m reveals interesting facts about cooling of cables with longer lengths. The defined cable length range at constant diameter (inner and annulus pipe) for the analysis was considered as 1.5–3 km. As a result, the maximum possible HTS cable length of 2.5 km can be achieved at the flow rate of 30 L/min and heat fluxes of 2.3–2.6 W/m within the defined operating range.