Investigation of heat transfer during magnetohydrodynamic flow of liquid metal in the “pipe in channel” heat exchange system

Abstract

Experimental studies of heat transfer during the upward flow of liquid metal in a vertical pipe, located axially inside a square heated channel connected to the natural circulation loop, were carried out. The measurements were performed in the absence and presence of a transverse magnetic field. Measurements both in the inner pipe and in the channel gap were carried out using longitudinal microthermocouple probes. Three main cooling modes are considered for the upward flow of mercury in the pipe and natural convective flow in the channel gap: the natural circulation loop is closed, the loop is opened, and cooling water of the cold leg is on or off. For the case of uniform heating of all sides of the outer channel, average temperature profiles, local heat transfer coefficients distributions, statistical characteristics of temperature fluctuation both in the pipe and in the channel gap were obtained in a wide range of Reynolds and Hartmann numbers. It was found that the flow configuration and its structure in the gap change significantly in the presence of a transverse magnetic field, and also depend on the inclusion of the natural circulation loop.