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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

The Effect of a Crossed Electromagntic Field on Mixed Convection of a Low Pr Fluid in a Vertical Duct

Get access (open in a dialog) DOI: 10.1615/IHTC15.hte.009259
pages 3965-3980

Résumé

The effect of imposed magnetic field on an electrically conducting buoyancy-opposed mixed convective flow down a vertical duct is numerically studied in the present paper. The heating from a specified uniform heat flux over a finite area is symmetric. The fluid is incompressible, Newtonian and Boussinesq approach is used for the treatment of buoyancy. The Prandtl number Pr, typical of high conducting liquid metals is low and taken to be (Pr = 0.01). Quasi-static approximation of Magnetohydrodynamic equations that ignores the induced magnetic field is used for flow –electromagnetic coupling. Joule heating is also neglected. The Navier-Stokes equations that include the buoyancy and Lorentz force terms, the Energy equation and a Poisson’s equation for the electric potential are semi-couple solved in an in-house developed finite volume flow solver. Results for planar mixed convection at a fixed Reynolds number Re = 1000 for increased buoyancy parameter |Gr/Re2| ? 5 is presented first that showed a change in the nature of solution from steady symmetric at lower values to quasi-periodic at higher values of buoyancy. At a lower Reynolds number (Re = 100) the flow oscillations are found to be symmetric dominant. Under an imposed magnetic field along the in-plane transverse direction, the oscillation amplitude is decreased but revealed a transformation from asymmetric to symmetric oscillations. The streamwise magnetic field is found to be not as dominant as that of the transverse field and showed a complex transitional flow at the highest strength considered in this study. The effect of an applied Electric field is found to act only on the bulk flow (pressure drop) with the transient characteristics virtually unaffected. A few remarks are made in the end on the three dimensional flow based on simulations performed on an aspect ratio (span width/height) = 2 duct which represents a work in progress.