Title: Magnetic damping of natural convection of an aqueous solution in a rectangular cavity having various aspect ratios

Authors: L. B. Wang, Nobuko I. Wakayama

Addresses: Lanzhou Railway Institute, Lanzhou, Gansu 730070, China. National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan

Abstract: In this paper, we numerically studied the magnetic damping of thermal convection in a low-conducting aqueous solution as a function of Grashof numbers (Gr), and Hartmann numbers (Ha), focusing on the effects of the aspect ratio of a rectangular container (0.1≤AR≤1AR). Two different magnetic field directions are considered. The ratio of averaged Nusselt number (Nuave) with and without magnetic field, Nur and the averaged velocity ratio, VaveB/Vave0 are used to quantify the degree of damping of natural convection. The results show that there exists an optimum AR for minimising natural convection, i.e., Nur when magnetic field is applied along Z-direction, but Nur increases with decreasing AR from 1 to 0.1 when magnetic field is applied along X-direction. The correlations of Nur and VaveB/Vave0 are given on parameters of AR, Ha and Gr. These results will be useful to determine the most efficient experimental conditions to damp natural convection during solidification of a material.

Keywords: aqueous solution; damping of convection; heat transfer; Lorentz force; low-conducting fluid; magnet field; natural convection; numerical simulation.

DOI: 10.1504/PCFD.2002.003218

Progress in Computational Fluid Dynamics, An International Journal, 2002 Vol.2 No.2/3/4, pp.80 -89

Published online: 19 Aug 2003 *

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