Double-Diffusive Convection from a Discrete Heat and Solute Source in a Vertical Porous Annulus

Abstract

This article reports a numerical study of double-diffusive convection in a fluidsaturated vertical porous annulus subjected to discrete heat and mass fluxes from a portion of the inner wall. The outer wall is maintained at uniform temperature and concentration, while the top and bottom walls are adiabatic and impermeable to mass transfer. The physical model for the momentum equation is formulated using the Darcy law, and the resulting governing equations are solved using an implicit finite difference technique. The influence of physical and geometrical parameters on the streamlines, isotherms, isoconcentrations, average Nusselt and Sherwood numbers has been numerically investigated in detail. The location of heat and solute source has a profound influence on the flow pattern, heat and mass transfer rates in the porous annulus. For the segment located at the bottom portion of inner wall, the flow rate is found to be higher, whereas the heat and mass transfer rates are higher when the source is placed near the middle of the inner wall. Further, the average Sherwood number increases with Lewis number, while for the average Nusselt number the effect is opposite. The average Nusselt number increases with radius ratio (λ); however, the average Sherwood number increases with radius ratio only up to λ = 5, and for λ > 5 , the average Sherwood number does not increase significantly.123 754 M. Sankar et al.

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Thermal effects of nonuniform heating in a nanofluid‐filled annulus: Buoyant transport versus entropy generation

“…Considering the various need of applications, until recently, buoyant convective thermal transfer in an annular geometry was numerically investigated by considering various external constraints and different thermal boundary conditions. [3][4][5][6][7][8] The inclusion of nanosized metals and oxides in traditional liquids was found to enhance the thermal transport rates and is corroborated through the predictions made by many theoretical simulations and experimental observations. 9,10 Thermal transport analysis of different nanofluids in annular geometries has also received a great amount of attraction due to the requirement for effective cooling of electronic equipment.…”

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