ABSTRACT:

Thermal convection is numerically computed in 3D fluid saturated fractured porous media. Fractures are inserted as 2D convex polygons, which are randomly located. The fluid is assumed to satisfy 2D and 3D Darcy's law in the fractures and in the porous medium, respectively; exchanges take place between these two structures. After some necessary comparisons with results relative to homogeneous porous media, systematic calculations are performed for Rayleigh numbers up to 150 for various values of the fracture density and the fracture aperture. The increase in output flux with fracture density is found to be linear over the range of fracture density tested. Moreover, the importance of the percolating character of the fracture network is emphasized. Finally, the effective medium approach is found to be precise only for small or large fracture densities.

1. INTRODUCTION

Simulation of natural convection in homogeneous porous media has attracted attention for many years (

Horton and Rogers, 1945; Lapwood, 1948; Nield, 1968; Combarnous and Bories, 1974

). To these few citations, many could be added. In contrast, only a few references can be cited for studies of natural convection through fractured porous media (

Kolditz, 1995; Blöcher et al., 2010; Bataillé et al., 2006

).Recently, detailed determination of flow through fractured porous media has been successfully addressed and

Adler et al., 2012

provide a systematic account of this theoretical and numerical effort.

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