Tuesday, October 4, 2011

HWR Seminar October 5th

Scale‐Invariant Estimates for Permeabilities of Porous Media

Dr. Larry Winter

Professor and Department Head

University of Arizona ~ Hydrology & Water Resouces

Three phenomenological power laws for the permeability of porous media are derived from computational experiments on flow through explicit pore spaces. The power laws relate permeability to (i) porosity, (ii) squared mean hydraulic radius of pores, and (iii) their product, which has units of length raised to the fifth power. We call (iii) the "Kozeny predictor" because it is the same independent variable as Kozeny used in his celebrated equation. The pore spaces are represented by three dimensional images of pore networks from seventeen virtual porous media. Images of two physical pore networks and other virtual media are used to independently assess the accuracy of the three models. Their performance is also compared to estimates derived via the Kozeny equation. The power laws provide tighter estimates than the Kozeny equation even after adjusting for the extra parameter they each require. The best fit is with the power law based on the Kozeny predictor. The power is approximately one third, so the law exhibits five‐thirds scaling with length.


Harshbarger Building Room 206 @ 4:00 pm ~

(Refreshments @ 3:45pm outside room 206)

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