Variable porosity and thermal dispersion effects on coupled heat and mass transfer by natural convection from a surface embedded in a non‐metallic porous medium

The problem of coupled heat and mass transfer by natural convection from a vertical impermeable semi‐finite flat plate embedded in a non‐uniform non‐metallic porous medium in the presence of thermal dispersion effects is formulated. The plate surface is maintained at constant wall temperature and concentration. The resulting governing equations are non‐dimensionalized and transformed using a non‐similarity transformation and then solved numerically by an implicit, iterative, finite‐difference scheme. A parametric study of all involved parameters is conducted and a representative set of numerical results is illustrated graphically to show typical trends of the solutions. It is found that the variable porosity of the porous medium and the effect of thermal dispersion result in increases in the local Nusselt number.