Experimental study on heat transfer characteristics of LBE flow in a vertical tube under static and rolling conditions

Abstract

The heat transfer characteristics of liquid metals get much attention because of their low Prandtl number. In this paper, the heat transfer characteristics of a heavy liquid metal (LBE) in a vertical circular test section under static and rolling motions are experimentally investigated. The results show that the additional forces induced by rolling motion cause a periodic change in the flow rate of the forced circulation. The rolling motion reduces the mean circulation flow rate, especially in the low flow rate region. The cycle-averaged heat transfer characteristics are significantly enhanced in the low Peclet number region (<2500). In the high Peclet number region (>2500), the cycle-averaged heat transfer characteristics are not significantly different compared to those under static condition. At low flow rates, flow rate oscillations may lead to counterflow. The amplitude of the Reynolds number oscillation, the cycle-averaged Reynolds number, the roll period and the roll amplitude jointly determine the cycle-averaged Nusselt number. The correlations under static conditions cannot predict the Nussle number under rolling conditions well. Therefore, a correlation is developed to analyze the heat transfer characteristics of LBE under rolling conditions. This study may contribute to the design and safety analysis of liquid metal heat transfer when applied to moving conditions.