Numerical Study of Chemically Reactive Buoyancy-Driven Heat and Mass Transfer across a Horizontal Cylinder in a High-Porosity Non-Darcian Regime

Abstract

We investigate the free convection boundary layer flow and heat and mass transfer across an isothermal cylinder embedded in an isotropic, homogenous, saturated porous regime with a first-order chemical reaction in the diffusing species. A Darcy-Forchheimer drag force model is implemented to simulate porous impedance effects in high-porosity media, which are encountered in various industrial and geophysical applications. The partial differential conservation equations are nondimensionalized and solved using a network simulation methodology. The effects of Darcy number, Forchheimer number, Schmidt number, and reaction parameter on dimensionless velocity, temperature, and species concentration distributions are studied in detail for the case of water of relevance to geohydraulic flows. Computations are also provided for the variation of local Nusselt number and local Sherwood number with various thermophysical parameters. Concentration is found to decrease continuously with distance into the boundary layer (y-coordinate) with an increase in chemical reaction parameter; values are markedly higher for the non-Darcian case than for the Darcian case. Temperatures are however increased by an increase in reaction parameter. Applications of the study include electrolysis processes, chemical filtration treatment systems, natural convection from buried waste canisters in geomaterials, geothermal systems, etc.