Characteristics of Heat Transfer in MHD Flow of Liquid Metal in a Tube-In-Channel Heat-Exchange System

The authors have conducted experimental investigations of heat transfer in upward flow of liquid metal in a vertical tube passing along the axis of a square heated channel incorporated in the contour of a natural-circulation loop. The measurements were carried out in the absence and in the presence of a transverse magnetic field. Use was made of probing measurement procedures with longitudinal microthermocouple probes in both the tube and the channel. Consideration has been given to three basic regimes of cooling in upward flow of mercury in the tube and its natural convective flow in the interchannel gap when the loop is shut off and when the loop is open without cooling and with cooling. For the cases of uniform heating of the channel in regimes with variable Reynolds and Hartmann numbers, the authors obtained the profiles of averaged temperature, the distributions of local heat-transfer coefficients, and the pulsation characteristics of temperature in the flows in the tube and in the channel gap. It has been found that the configuration of flow and its structure in the gap change substantially upon applying the transverse magnetic field, and also depending on the operating regime of the natural-circulation loop.