Enhancement of heat and mass transfer rates through various porous cavities for triple convective-diffusive free convection

Abstract

Convective energy and mass transfer in various porous chambers are a wide-spread physical phenomenon in natural and technical systems. The triple diffusive free convection is examined in square, trapezoidal and triangular porous chambers under an impact of internal volumetric heat generation. The top and bottom surfaces of the chambers are assumed to be adiabatic and impermeable. In this study, different concentrations of NaCl and Sucrose are utilized as solutal components with water. Governing equations written employing the linear Darcy model and non-primitive dimensionless variables were worked out by the finite element technique with the Galerkin method of weighted residuals. The influence of the internal heat generation rate, Rayleigh and Lewis numbers, buoyancy ratios on the dimensionless temperature, the concentration of both salts, Nusselt, Lewis and Sherwood numbers are scrutinized. The study reveals that the growth of the inner volumetric heat flux raises the temperature within the cavity and reduces the Nusselt number, while the Sherwood and Nusselt numbers are raised with the buoyancy ratio parameter. Also, the triangular cavity shows the highest heat and mass transfer rate.