Permeability and Thermodiffusion Effect in a Porous Cavity Filled with Hydrocarbon Fluid Mixtures

Abstract

This paper investigates numerically the in- teraction between thermodiffusion and buoyancy driven convection in a laterally heated vertical porous cavity for different values of the permeability. The Firooz- abadi model is applied to several binary hydrocarbon mixtures: (i) a mixture of 1,2,3,4 tetrahydronaphtalene (THN) and dodecane (C12) with mass fraction of 50% for each component, (ii) 1,2,3,4 tetrahydronaphtalene and isobutylbenzene (IBB) with mass fraction of 50% for each component, and (iii) isobutylbenzene and do- decane with mass fraction of 50% for each component. The thermal and molecular diffusion coefficients, which are functions of the temperature and other properties of the mixture, are calculated at each point of the grid. Nu- merical results reveal that when the permeability is low the thermodiffusion effect is dominant in the composi- tion separation process. As the permeability increases the thermodiffusion effect and buoyancy-driven convec- tion combine their actions to enhance the composition separation process. As the permeability increases fur- ther the buoyancy-driven convection becomes dominant in thecavity and becomes detrimentalto separationin the cavity.