Thermal mixing enhancement of liquid metal film-flow by various obstacles under vertical magnetic field

Abstract

Heat removal techniques of various liquid divertor concepts have been widely studied. In this study, thermal mixing characteristics of the liquid metal film-flow with locally heated on the surface under the vertical magnetic field were experimentally investigated by using various types of obstacles as a vortex generator. Especially, the efficiency of heat transport was investigated by the thermocouples installed on the bottom-wall. The velocity distributions were measured using the electric potential probe rake on the downstream of the channel. A delta-wing, a hemisphere or a cubic obstacle was used as a vortex generator installed at the center of the bottom-wall. The experiments were conducted for laminar flow region where Re = 487–1583 and in the range of N (=Ha2/Re) = 0–149 in the vertical magnetic field in the acrylic rectangular duct. GaInSn alloy was used as a working fluid. According to the comparison of heat flux distributions on the bottom-wall, the entire distributions moved towards the upstream with increasing of the strength of the vertical magnetic field for all cases. This tendency means the heat removal from the free-surface of liquid metal film-flow to the bottom-wall can be shortly achieved in case of the relatively high vertical magnetic field.