Numerical simulation of fluid flow through random packs of ellipses
Abstract
The effect of particle shape on permeability is investigated by means of numerical methods of fluid flow through two-dimensional, periodic, random packs of ellipses. We solve the unsteady Navier-Stokes equations on a Cartesian grid and use the immersed boundary method to treat internal flow boundaries. The effect of porosity, aspect ratio, and Reynolds number on the macroscopic permeability and tortuosity is studied. For small Reynolds numbers, it is shown that an area-preserving deformation of a pack of disks, generating a pack of ellipses, can lead to significant variations in the permeability. However, if the ellipses are randomly packed, so that the alignment of their axes is random, the shape effect is small. Irrespective of orientation, the aspect ratio has a strong effect on the tortuosity at all values of the porosity. We also show that the parameters in the Carman-Kozeny equation are not constant but are functions of porosity and aspect ratio. For larger Reynolds numbers, we show results for random packs of bidisperse and polydisperse cylinders, as well as for ellipses. We find that a modified Forchheimer equation can well characterize the flow.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Feb 01, 2015
- Source ID
- 10.1063/1.4907409
Entities
People
- D. Jenne
- T. L. Jackson
- Y. Matsumura
Organizations
- Defense Threat Reduction Agency
- United States Department of Energy
- University of Florida
- University of Illinois Urbana–Champaign
- École Centrale de Lille