Letter | Published:

Measurement of Slip (Ko) and Viscous (Bo) Flow Coefficients of Permeable Solids

Naturevolume 187page865 (1960) | Download Citation



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 , 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 ), 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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  1. 1

    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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  1. English Electric Co., Ltd., Marconi House, Strand, London, W.C.2

    • J. G. BIRAM


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