Parametric studies on entropy generation rate in dual channel cable-in-conduit conductors (CICCs) with supercritical helium (SHe) using computational fluid dynamics

Abstract

Dual channel cable-in-conduit conductors (CICC) are used in the construction of superconducting magnets of Tokamak machines. These superconducting magnets are cooled with supercritical helium (SHe) to maintain the superconductors below the critical temperature. Thermophysical properties of SHe such as density, viscosity, specific heat and thermal conductivity vary drastically above the supercritical temperature and pressure (4.5 K and 0.5 MPa). Hence, thermohydraulic characterizations of dual channel CICCs using SHe as coolant is one of the complex tasks. In continuation with the earlier studies on supercritical helium with regard to the estimation of pressure drop, heat transfer and entropy generation, the present work focuses its attention on parametric studies on entropy generation rate due to flow of SHe in dual channel CICC. Further, influence of parameters such as porosity and inlet temperature of the SHe on rate of entropy generation are presented. In addition, optimum mass flow rate required to maintain dual channel CICC in economic operation are recommended using the Entropy Generation Minimization (EGM) technique.