Investigation of MHD Heat Exchange in a Liquid Metal Flow through a Tube-in-Channel System under Conditions Close to the Thermonuclear Reactor Blanket Module

Heat exchange in a liquid metal upward flow through a tube-in-channel system has been studied experimentally and analytically. The system consists of a vertical tube passing along the axis of a square heated channel that is connected to a natural circulation loop. Experiments have been conducted in the presence of a transverse magnetic field and without it. Probe measurements using longitudinal microthermocouple probes placed both in the tube and in the channel gap have been applied. Heat exchange averaged characteristics have been numerically simulated for experimental conditions. Three basic operating conditions of the cooling loop have been considered: the loop is shut off, the loop is open allowing free circulation in the gap without cooling, and the loop is open and provides cooling. In experiments, the profiles of averaged temperature, the distributions of heat transfer local coefficients, and the pulsation characteristics of flow temperature both in the tube and in the channel gap have been obtained. Calculation data have been compared with experimental results. It has been found that the configuration and structure of the flow significantly depend on the presence of transverse magnetic field and on whether the natural circulation loop is connected and provides cooling.