Buoyancy effects on upward and downward laminar mixed convection heat and mass transfer in a vertical channel

Abstract

International audienc

Flow reversal of laminar mixed convection in the entry region of symmetrically heated, vertical plate channels

“…Up to now, apart from a few isolated investigations, no systematic study of the occurrence of recirculation cells in the developing flow region in symmetrically heated vertical channel at constant temperature has been performed. Most have failed to evidence such recirculation cells [18,19,22], except in [20]. The overall focus of this study was to obtain quantitative information on the effects of recirculation cells associated with flow reversal on hydrodynamic and heat transfer in vertical parallel-plate channels of finite length.…”

“…Ingham et al [20] found flow reversal near the centre of a parallel-plate duct with symmetric wall temperature boundary conditions for two values of the Gr/Re parameter, 350 and 600. Azizi et al [22] in a recent numerical study only showed recirculation occurrence in the case of opposing flow (i.e., along the walls) but they examined only a few particular cases. Some attempts at numerical simulations of flow reversal in the entrance region of a rectangular duct have been reported by Cheng et al [23] but no reversed flow in the centre part of the duct was put in evidence.…”

Experimental and numerical study of mixed convection heat and mass transfer in a vertical channel with film evaporation

“…An increase of the inlet air temperature results in a small increase of the sensible Nusselt number and a significant decrease of the latent Nusselt number. Azizi [25] studied numerically the buoyancy effects on upward and downward laminar mixed convection heat and mass transfer in a vertical channel. Flow reversal was predicted for upward flow with high inlet temperature.…”

Mixed Convection Heat and Mass Transfer with Phase Change and Flow Reversal in Channels

“…This technique gives a more accurate estimation of the temperature gradients at the wall (and, hence, the heat transfer coefficient) than Nusselt's theory, which ignores the inertial effects. An interesting way to deal with the liquid film modelling was used by some authors (Lin et al 1988;Yan 1993;Fedorov et al 1997;Volchkov et al 2004;Huang et al 2005;Azizi et al 2007;Laaroussi et al 2009;Oulaid et al 2010b). These authors assumed an extremely thin liquid film so that it could be treated as a boundary condition.…”