Buoyancy effects on developing laminar gas flow and heat transfer in a rectangular fuel cell duct

Using general 3-D finite-volume code, the development of buoyancy force sec ondary flow and its effects on developing laminar flow and heat transfer ha ve been numerically simulated for a horizontal fuel cell duct with a rectan gular cross section. The constant thermal-properties assumption except for linear density variation with temperature in the body force term is applied , and a constant heat flux is prescribed on the bottom wall, while thermal insulation is implemented on the other three walls. The secondary flow form s vortices in the duct that can disrupt both hydrodynamic and thermal bound ary layer and enhance friction factor and heat transfer. Calculations have been performed to determine the effects of various Grashof number Gr* and R eynolds number Re. Comparisons of these numerical results with available ex isting data are presented. This study may be regarded as an improved modeli ng procedure for gas flow and convective heat transfer in fuel cell ducts.