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Flow and transport in single rock fractures

Published online by Cambridge University Press:  26 April 2006

K. Muralidhar
Affiliation:
Department of Mechanical Engineering, Indian Institute of Technology, Kanpur 208016, India

Abstract

The present work is a numerical study of fluid flow and energy transport in single rock fractures. Each fracture is modelled as a parallel channel with a distribution of contact areas where the fracture aperture is zero. The pressure drop required to sustain a given rate of flow is calculated by solving the Stokes equations along with the incompressibility constraint. The permeability of the fracture is then determined as the ratio of mean flow and pressure drop. With flow distribution known, the advection–diffusion equation is solved for a thermal mixing problem. All differential equations have been solved by the finite-element technique.

Results show that the fracture permeability is affected by the presence of contact areas and the magnitude of h, the mean fracture aperture. The limiting case of zero aperture is realized at h/L [les ] 0.016, where L is the characteristic dimension of the fracture. The other limiting case of a two-dimensional fracture is seen for h/L [ges ] 1. The thermal dispersion profiles at steady state are unaffected by the size of aperture h and the presence of contact areas for Péclet numbers Pe less than 50 and a contact fraction of up to 20%. However, the transient dispersion problem is seen to be influenced by the contact areas for Pe > 10.

Type
Research Article
Copyright
© 1990 Cambridge University Press

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