HR: 1340h
AN: T53C-1450    [Abstracts]
TI: Permeability-porosity relationship in a stochastic model of partial melting
AU: * Riedel, M R
EM: miker@geo.uni-potsdam.de
AF: University of Potsdam, Department of Geosciences, Karl-Liebknecht-Str. 24, Golm, 14476 Germany
AU: Lammers, P
EM: plammers@hlrs.de
AF: High Performance Computing Center (HLRS), Allmandring 30, Stuttgart, 70550 Germany
AB: We present a model for calculating permeability of a porous solid-melt polycrystal during melting. Unlike to previous two-phase models, a solid framework is used that does not have a regular geometry nor a typical grainsize. Instead, we use a polycrystal that is created on the basis of a stochastic nucleation and growth process for first-order phase transformations as the starting state for partial melting. It is a polycrystal with continuously distributed grainsizes and random grain locations. Permeability is then estimated through flow simulation on the constructed 3D porous two-phase body using the Lattice-Boltzmann (LB) technique. The LB method describes fluid motion with the interaction of a massive number of particles following simple local rules, rules that recover the Navier-Stokes equation at the macroscopic scale [Rothman and Zaleski, 1997]. It is known that the LB flow simulation is able to handle successfully very complex 3D pore geometries [Keehm et al., 2004]. Here, the investigated porous framework shows a fractal-like geometry near to percolation of either melt or solid phase. The flow simulation is done with an assigned pressure gradient ∇ P across opposite faces of cubes. From the local flux, the volume-averaged flux < q > is then calculated using Darcy's relationship
< q > = - κ η̅ ∇ P
where κ is the (wanted) macroscopic permeability and η is the dynamic viscosity of the melt. References: Keehm Y., T. Mukerji T. and A. Nur. Permeability prediction from thin sections: 3D reconstruction and Lattice-Boltzmann flow simulation. GRL, 31, L04606, doi: 10.1029/2003GL018761, 2004.
Rothman D.H. and S. Zaleski. Lattice-Gas Cellular Automata. Cambridge University Press, Cambridge, 1997.
DE: 3619 Magma genesis and partial melting (1037)
DE: 5112 Microstructure
DE: 5114 Permeability and porosity
SC: Tectonophysics [T]
MN: Fall Meeting 2005