Internal heat generation/or absorption phenomena in three-dimensional natural convection flow within enclosure filled with different working fluids

Purpose: The purpose of this study is to investigate the effects of heat generation or absorption on heat transfer and fluid flow within two- and three-dimensional enclosure for homogeneous medium filled with different metal liquid. Numerical results are presented and analyzed in terms of fluid flow, thermal field structures, as well as average Nusselt number profiles over a wide range of dimensionless quantities, Grashof number (Gr) (104 and 105), SQ (varied between −500 to 500) and Prandtl number (Pr = 0.015, 0.024 and 0.0321). The results indicate that when the conductive regime is established for a Grashof number Gr = 104, the 2D model is valid and predicts all three-dimensional results with negligible difference. This was not the case in the convective regime (Gr = 105) where the effect of the third direction becomes important, where a 2D-3D difference was seen with about 37 per cent. Also, in most cases, the authors find that the heat absorption phenomena have the opposite effect with respect to the heat generation. Design/methodology/approach: Numerical results are presented and analyzed in terms of fluid flow, thermal field structures, as well as average Nusselt number profiles over a wide range of dimensionless quantities. Findings: Grashof number (Gr) (104 and 105), SQ (varied between −500 to 500) and Prandtl number (Pr = 0.015, 0.024 and 0.0321). Originality/value: The results indicate that when the conductive regime is established for a Grashof number Gr = 104, the 2D model is valid and predicts all three-dimensional results with negligible difference. © 2018, Emerald Publishing Limited.