Buoyancy effects on upward and downward laminar mixed convection heat and mass transfer in a vertical channel
International Journal of Numerical Methods for Heat & Fluid Flow
ISSN: 0961-5539
Article publication date: 3 April 2007
Abstract
Purpose
The objective of the present study is to investigate numerically the effects of thermal and buoyancy forces on both upward flow (UF) and downward flow (DF) of air in a vertical parallel‐plates channel. The plates are wetted by a thin liquid water film and maintained at a constant temperature lower than that of the air entering the channel.
Design/methodology/approach
The solution of the elliptical PDE modeling the flow field is based on the finite volume method.
Findings
Results show that buoyancy forces have an important effect on heat and mass transfers. Cases with evaporation and condensation have been investigated for both UF and DF. It has been established that the heat transfer associated with these phase changes (i.e. latent heat transfer) may be more or less important compared with sensible heat transfer. The importance of these transfers depends on the temperature and humidity conditions. On the other hand, flow reversal has been predicted for an UF with a relatively high temperature difference between the incoming air and the walls.
Originality/value
Contrary to most studies in channel heat and mass transfer with phase change, the mathematical model considers the full elliptical Navier‐Stokes equations. This allows one to compute situations of flow reversal.
Keywords
Citation
Azizi, Y., Benhamou, B., Galanis, N. and El‐Ganaoui, M. (2007), "Buoyancy effects on upward and downward laminar mixed convection heat and mass transfer in a vertical channel", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 17 No. 3, pp. 333-353. https://doi.org/10.1108/09615530710730193
Publisher
:Emerald Group Publishing Limited
Copyright © 2007, Emerald Group Publishing Limited