Double diffusion in a combined cavity occupied by a nanofluid and heterogeneous porous media

Abstract

Abstract The aim of the present study is to simulate double diffusion in a circular cylinder over a rectangular cavity by utilizing incompressible smoothed particle hydrodynamics (ISPH) method. An originality of this study is adopting the ISPH method in simulating double diffusion in a novel domain of a circular cylinder over a rectangular shape occupied by Al 2 O 3 {{\rm{Al}}}_{2}{{\rm{O}}}_{3} – H 2 O {{\rm{H}}}_{2}{\rm{O}} and heterogeneous porous media. The variations of Darcy parameter (Da) between 1 0 − 3 1{0}^{-3} and 1 0 − 5 1{0}^{-5} with two levels of porous media, ( 0 ≤ η 1 = η 2 ≤ 1.5 ) (0\le {\eta }_{1}={\eta }_{2}\le 1.5) , Rayleigh number ( 1 0 3 ≤ Ra ≤ 1 0 5 ) (1{0}^{3}\le {\rm{Ra}}\le 1{0}^{5}) with variable buoyancy ratio parameter ( 0 ≤ N ≤ 2 ) (0\le N\le 2) , solid volume fraction ϕ \phi between 0 and 0.05, and Lewis number ( 10 ≤ Le ≤ 40 ) (10\le {\rm{Le}}\le 40) on the features of heat/mass transport as well as velocity field are discussed. It is found that the homogeneous porous medium reduces the temperature and concentration within a combined cavity. A decrease in Darcy parameter from 1 0 − 2 1{0}^{-2} and 1 0 − 5 1{0}^{-5} suppresses the maximum of a nanofluid velocity by 75% regardless the levels of porous media. An increase in parameters Ra and N enhances the heat and mass transmission, as well as the nanofluid velocity. Adding more concentration of nanoparticles until 5 % 5 \% reduces the nanofluid velocity. The variations of boundary conditions are acting effectively in changing the temperature and concentration circulations within a combined cavity. Besides, the variations of boundary conditions change the maximum of the velocity field by 86.9%.