Natural Convection Heat Transfer of Liquid Lithium under Transverse and Parallel Magnetic Fields

Abstract

Stagnant liquid lithium contained in a vertically 1.3 m long and 46 mm I.D. 316-SS cylindrical vessel up to a 0.3 m level was heated by a concentrically inserted heater pin of 12.5 mm O.D. and 54 mm active length. The parallel magnetic field to the vessel was imposed by a superconducting magnet. The experiment covered the ranges of the lithium temperature: 320∼510°C, the heat flux: 10∼40 W/cm2, the transverse B: 0∼1.2 T (Ha = 0∼2,730) and the parallel B= 0∼3T (Ha = O∼6,860). The temperature fluctuation is enhanced by imposing a weak magnetic field of B = 0.1 ∼ 0.3 T for both parallel and transverse fields and almost completely suppressed with increasing to B = 1 T in the case of the transverse field but its low frequency component still remains large, becoming oscillatory, up to B = 3 T in the case of parallel field. The heat transfer shows a similar trend to the temperature fluctuation. It increases singularly by a weak B especially in the perpendicular sector to the transverse magnetic field and decreases with increasing B. In the case of parallel magnetic field, the heat transfer increases in a weak field of B = 0.1 ∼ 0.5 T, the same as in the transverse magnetic field, but it does not decrease so much in a strong field of B = 1∼3 T, presenting a rather higher value than in B = 0 T.