Permeability Studies: Ii. Surface Area Measurements of Inorganic Pigment Powders

Arnell, J. C.

doi:10.1139/cjr47a-019

Cited by 13 publications

(8 citation statements)

References 2 publications

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“…If values of A and B are available from experiment, then L can be calculated from Equation ( 8 ) , the expression for A, and C can be found from Equation (lo), which is apparently correct to within about 3%.…”

Section: 'mentioning

confidence: 99%

The flow of rarefied gases

Scott

Dullien

1962

AIChE Journal

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It has been shown experimentally by Knudsen and others that gases flowing a t decreasing total pressures through small capillaries pass from a region of Poiseuille flow to a so-called slip flow region which contains a flow minimum. Frequently the practice has been followed of approximating this behavior with a linear relationship which, although it gives a fairly good approximation to the actual curve, is incomplete in theory. Some discussion of the use of this equation in the design of vacuum piping and its applicability to flow through porous solids is also given.

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Section: 'mentioning

confidence: 99%

The flow of rarefied gases

Scott

Dullien

1962

AIChE Journal

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“…These are generally based on an idealized model of the medium consisting of parallel capillaries and the constants in the viscous/slip equation for a uniform capillary are modified to correct for the shape and tortuosity of the pores in the actual media. They were derived by Kozeny (1927), Carman (1937) and Adzumi (1937) and developed by Carman (1937), Arnell (1946Arnell ( , 1947, Lea & Nurse (1947) and Carman & Arnell( 1948), in order to assess pore properties, primarily specific surface, from gas flow measurements. Although they have limitations, they do provide a useful means of estimating the order of magnitude of the diameter of the flow paths through porous media.…”

Section: The Mechanism Of Flow Of Gases Through Coniferous Wood 207mentioning

confidence: 99%

The mechanism of flow of gases through coniferous wood

Smith

Banks

1971

Proc. R. Soc. Lond. B.

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The mechanism of flow of gases through coniferous wood has been examined and found to follow the viscous/slip régime. According to the general theory the specific flow K of a gas in this régime is a linear function of its mean pressure p̅. For coniferous wood, however, we have found that K is a quadratic function of p̅ approximating to a linear one at high enough values of p̅ . It is shown that this is because K is the sum of two linear functions of p̅ , k 1 and k 2 such that 1/ K = 1/ k 1 + 1/ k 2 where k 1 is believed to be the flow through the tracheids alone and k 2 the flow through the bordered pits. It is shown that the permeability constant for viscous flow K v calculated from gas flow is applicable to liquids so that liquid flow can be predicted from gas flow data. With some species the observed flow rate of a liquid differs greatly from the predicted value. Evidence has been obtained that this is because the torus and margo fibrils of the bordered pit are readily displaced by the surface tension and momentum forces developed on them by a liquid causing radical and erratic changes in permeability. Approximate values for the ‘diameter̕ of the smaller flow path have been calculated from the ratio of the viscous to the slip component of flow of k 2 . These were found to be about 1.4 to 1.7 μ m. This is the same order of size as the distances between the torus and the interior of the border of the pit and indicates that it is the geometry of this part of the structure, rather than that of the margo, that controls flow. These results provide strong support for the modern theory of pit structure based on electron microscope photographs.

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“…Notable among them are the equations of Darcy (14), Kozeny (21), Adzumi (1-4), Carman (lo), and Arne11 (6)(7). Practically all of these equations have certain features in common which are perhaps most conveniently discussed by references to Adzumi's equations.…”

Section: The Adzumi Equationmentioning

confidence: 95%

The Flow of Fluids Through Activated Carbon Rods.

Flood¹,

Tomlinson²,

Léger³

1952

Can. J. Chem.

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The flow rates of the vapors of benzene, ethyl chloride, diethyl ether, methanol, and water through activated carbon rods have been found to exceed, considerably, flow rates calculated by classical equations. The excess flow rates show maxima in widely different relative pressure regions and are ascribed t o flow of adsorbed material. An empirical equation is presented which correlates the observed flour rates with relevant adsorption isotherms. Classical equations of flow through elliptical and rectangular pipes are discussed with reference to flow through finegrained porous materials. I t is shown that equations of the Adzumi type are roughly valid as applied to line-grained porous bodies, but that without a knowledge of the frequency distributions of pore sizes and shapes, flow data cannot be related to pore dimensions in any literal sense. End effects are discussed.

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Permeability Studies: Ii. Surface Area Measurements of Inorganic Pigment Powders

Cited by 13 publications

References 2 publications

The flow of rarefied gases

The flow of rarefied gases

The mechanism of flow of gases through coniferous wood

The Flow of Fluids Through Activated Carbon Rods.

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