Geometrical percolation threshold of overlapping ellipsoids

来自掌桥科研

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阅读量：

145

作者：

EJ Garboczi，KA Snyder，JF Douglas，MF Thorpe

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摘要：

A recurrent problem in materials science is the prediction of the percolation threshold of suspensions and composites containing complex-shaped constituents. We consider an idealized material built up from freely overlapping objects randomly placed in a matrix, and numerically compute the geometrical percolation threshold pwhere the objects first form a continuous phase. Ellipsoids of revolution, ranging from the extreme oblate limit of platelike particles to the extreme prolate limit of needlelike particles, are used to study the influence of object shape on the value of p. The reciprocal threshold 1/p(pequals the critical volume fraction occupied by the overlapping ellipsoids) is found to scale linearly with the ratio of the larger ellipsoid dimension to the smaller dimension in both the needle and plate limits. Ratios of the estimates of pare taken with other important functionals of object shape (surface area, mean radius of curvature, radius of gyration, electrostatic capacity, excluded volume, and intrinsic conductivity) in an attempt to obtain a universal description of p. Unfortunately, none of the possibilities considered proves to be invariant over the entire shape range, so that pappears to be a rather unique functional of object shape. It is conjectured, based on the numerical evidence, that 1/pis minimal for a sphere of all objects having a finite volume.

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关键词：

SPHERICAL PARTICLE LAYER FORCED CONVECTION HEAT TRANSFER NONHOMOGENEOUS POROUS LAYER EFFECTIVE THERMAL CONDUCTIVITY TEMPERATURE BOUNDARY LAYER

DOI：

10.1103/PhysRevE.52.819

被引量：

764

年份：

1995