LAMINAR AND TURBULENT NATURAL CONVECTION WITHIN IRREGULARLY SHAPED ENCLOSURES

Publisher Website
Google Scholar
Abstract
A numerical investigation is performed in the area of two-dimensional steady-state natural convection heat transfer within enclosures of general irregular geometry with differentially heated opposing wails. A stream function-vorticity formulation is adopted and the two-equation k-ε model of turbulence is used. Geometric irregularity is allowed for through the choice of the boundary-fitted coordinate system solution approach encompassing numerical grid generation. Prespecified grid control functions are employed to accomplish the concentration of nodal points in near-wall regions. A modified control volume integration solution technique is formulated with upwind differencing of the convective terms. The solution methodology is validated through a comparison with previously reported results for flows within tilted rectangular enclosures. Results are then presented for the flow of air within irregularly shaped enclosures containing geometrically contracted regions for Rayleigh numbers up to 10 8 S. M. ElSherbiny , K. G. T. Hollands , and G. D. Raithby , Effect of Thermal Boundary Conditions on Natural Convection Across Vertical and Inclined Air Layers , ASME J. Heat Transfer , vol. 104 , pp. 515 – 520 , 1982 . [Google Scholar] It is found that contractions effectively pinch off laminar flows, whereas they do not confine turbulent flows. In all cases, maximum heat transfer rates are found near regions of geometric contraction.