A NUMERICAL STUDY OF THERMAL DISPERSION IN POROUS-MEDIA

Thermal dispersion in convective flow in porous media has been numeric ally investigated using a two-dimensional periodic model of porous str ucture. A macroscopically uniform flow is assumed to pass through a co llection of square rods placed regularly in an infinite space, where a macroscopically linear temperature gradient is imposed perpendicularl y to the flow direction. Due to the periodicity of the model, only one structural unit is taken for a calculation domain to resolve an entir e domain of porous medium. Continuity, Navier-Stokes and energy equati ons are solved numerically to describe the microscopic velocity and te mperature fields at a pore scale. The numerical results thus obtained are integrated over a unit structure to evaluate the thermal dispersio n and the molecular diffusion the to tortuosity. The resulting correla tion for a high-Peeler-number range agrees well with available experim ental data.