HEAT-TRANSFER FROM ALUMINUM TO HE-II - APPLICATION TO SUPERCONDUCTIVE MAGNETIC ENERGY-STORAGE

Heat transfer problems associated with large scale Superconductive Magnetic Energy Storage (SMES) are unique due to the proposed size of a unit. The Wisconsin design consists of a cryogenically stable magnet cooled with He II at 1.8 K. The special properties of He II (T < 2.17 K) provide an excellent heat transfer medium for magnet stability. Design values are determined from an experimental study of heat transfer from aluminum to He II. Under near saturated conditions we observe a maximum surface heat flux of 1. 7 W/cm2 at 1.91 Kanda recovery at 0.7 W/cm2 The advantages of operating the magnet under subcooled conditions are exemplified by improved heat transfer. The maximum at 1.89 K and 1.3 atm pressure is 2.3 W/cm2 with recovery enhanced to 1.9 W/cm2. A conservative maximum heat flux of 0.5 W/cm2 with an associated temperature difference of 0.5 K has been chosen for design. Elements of the experimental study as well as the design will be discussed. © 1979 by ASME.