Liquid nitrogen flow in helically corrugated pipes with insertion of high-temperature superconducting power transmission cables

Abstract

The pressure drop behavior of cryogenic flow in corrugated pipes is a critical design parameter for high-temperature superconducting (HTS) power transmission line systems. Most studies on the pressure loss and temperature increase of liquid nitrogen (LN2) flow in annularly corrugated pipes in the literature have focused on pipe geometries. However, the positioning and configuration of the HTS cables in the corrugated shell tube are also of great concern in practical applications. Moreover, helically corrugated pipes are used more frequently than annular pipes for the long-distance deployment of HTS transmission lines. This study investigates the influence of cable insertion and configuration in helically corrugated pipes on the surrounding subcooled LN2 flow, in terms of the pressure loss and temperature profiles. Triple and quadruple cables with diameters of 5 and 8 mm configured in different forms in a Φ40 mm helically corrugated pipe are comparatively studied using a three-dimensional model. Correlations among the equivalent diameter, Nusselt number, and Reynolds number are proposed for predicting the heat transfer of LN2 flow in helically corrugated pipes.