Two-dimensional numerical simulation of thermo-gravitational convection in a vertical porous column filled with a binary fluid mixture

Abstract

Convection has a very important effect on the thermal diffusion process in hydrocarbon porous media. We investigate the convection effect in a vertical cavity having an aspect ratio of 10 and subject to a lateral heating condition based on two-dimensional numerical simulation. Using the irreversible thermodynamics theory of Shukla and Firoozabadi [Ind. Engrg. Chem. Res. 37 (1998)], the space dependent thermal, molecular and pressure diffusion coefficients are calculated at each point of the grid as functions of the temperature, pressure and other properties of the mixture. The thermal diffusion process is simulated in a vertical porous media combined with natural convection flow over a range of permeability from 0.001 to 10 000 md. Numerical results reveal that the lighter fluid component migrates to the hot side of the cavity, and as the permeability increases, the component separation in the thermal diffusion, or Soret effect, process increases first, reaches its peak, and then decreases. This phenomenon is illustrated and discussed both numerically and physically.