Abstract
IT is usual to measure the slip (Ko) and viscous (Bo) flow coefficients of permeable solids by plotting as a function of mean specimen pressure p̄, and using the slope and intercepts of the curve to find Bo and Ko. It is also possible to find Bo and Ko in one measurement (at a single p̄), of K, p1 (inlet), P0 (outlet) and the centre-specimen pressure. By knowing that the mass flow : and b = Bo/η (η is gas viscosity), and that the divergence of Qm is zero (Z – axial flow only, that is, a rod or bar test-piece), a pressure distribution p(Z) can be calculated ; by putting p(Z) = p(½), that is, pressure half-way along the bar-length (Z = L/2), a/b can be found as : by measurements of pressures at three points, independently of flow. Since by finding K from flow measurements, b can be found, and hence a : that is, Bo and Ko can be found.
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References
Hutcheon, J. M., et al., “Flow of Gases through a Fine-Pore Graphite”. S.C.I. Carbon Conference paper (Sept. 1957).
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BIRAM, J. Measurement of Slip (Ko) and Viscous (Bo) Flow Coefficients of Permeable Solids. Nature 187, 865 (1960). https://doi.org/10.1038/187865a0
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DOI: https://doi.org/10.1038/187865a0
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