Simulation and Optimization of Cryogenic Heat Sink for Superconducting Power Cable Applications

Superconducting power devices require cable terminations to intercept the heat inleaks from the ambient temperature, thus, maintaining the superconducting cable within operating cryogenic temperature limits. Owing to the possible safety hazards such as asphyxiation and cold burns resulting from the use of liquid cryogen, use of gaseous Helium as a possible cooling medium for superconducting power devices is being considered. Also, the use of helium gas facilitates operation of the superconducting device at temperatures much lower than even sub-cooled liquid Nitrogen, thereby, increasing their critical current density. A model is being developed using the finite element method (FEM) to study the feasibility of a helium gas cooled heat sink to be used as a cable termination. The results obtained from the simulation model are validated with an experimental setup. The numerical coolant temperature and pressure drop as well as the heat sink temperature correspond well with the experimental results. Furthermore, the heat sink is geometrically optimized for given mass flow rate and input conditions to produce a better thermal and fluid performance in terms of temperature gain and pressure loss. It is found that an unequally spaced heat sink, which distributes the flow uniformly across all the channels, is more effective and gives better performance.