Pore-Size Distribution in Textiles-A Study of Windproof and Water-Resistant Cotton Fabrics

Wakeham, Helmut; Spicer, Nancy

doi:10.1177/004051754901901105

Cited by 26 publications

(12 citation statements)

References 4 publications

(8 reference statements)

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“…This is much larger than the average optically projected open area dimension of 0.3 X 0.3 mm square openings in X. The area of the group of channels going turbulent in zone 1 (i. e., DA 1 ) from Equation 10 for B = 0.67, OPT;/T = 0.202 and R 1 = 0.76 and RO = 5.34, is A 1 = 0,4 lA. In zone 2, T2 is the antilog of 0.7 or 2.01.…”

Section: B Values For Added Flowsmentioning

confidence: 92%

“…By definition, for B = 1, R = oo, therefore the portion of the total area A that becomes turbulent at zone 0 from Equation 10 is 0.40 = A/( 1 + 1.06) -A/( 1 + oo) = 0.48A. The area of the group of channels going turbulent in zone 1 (i.e., dA 1) at OPT,/T is computed from Equation 10 using R1 of B1 = 0.5, which equals zero for any API T level, and RO = 1.06, which is ~.41 = A/( 1 + 0) - Table I). …”

Section: B Values For Added Flowsmentioning

confidence: 99%

“…Such efforts are often confused by changes in the nature of the flow over the pressure range used and by the difficulties of dealing with a combination of linear and nonlinear or turbulent flow in separate channels. Burleigh [21 and Wakeham [ 10] used mercury intrusion methods to determine pore size and distribution of structures. This technique relates the radii of pores to the pressure at which inflection points occur in a pressure-flow curve.…”

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A New Method for Pore Structure Analysis Using Air Flow

Hassenboehler

1984

Textile Research Journal

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A new method of analyzing the absolute sizes and distribution of flow channels in porous textiles open to air flow is introduced. The state of the air flow through a textile over a range of pressure drop is ascribed to additive effects of linear or nonlinear flow in separate flow channels. Changes in flow status in given size channels with pressure produce identifiable inflection or transition points that are assumed to occur as the air attains a universal critical shear stress for air in any channel. The inflection points are resolved using a modified permeometer. A force description of the flow relationship in terms of pressure drop, shear stress, and the channel diameter allows all absolute structure information to be evaluated. Relative and absolute sizes of individual flow channels are determined from the transition differential pressure associated with the flow transformation in individual channels. The exponent of the power function describing the flow over a given pressure drop region is related to the open areas experiencing laminar and turbulent flow and is used to determine relative areas having a given size channel.Air flow through porous textile structures has been studied by many investigators with the ongoing aim of analyzing textile structural features from flow properties. Such efforts are often confused by changes in the nature of the flow over the pressure range used and by the difficulties of dealing with a combination of linear and nonlinear or turbulent flow in separate channels.Burleigh [21 and Wakeham [ 10] used mercury intrusion methods to determine pore size and distribution of structures. This technique relates the radii of pores to the pressure at which inflection points occur in a pressure-flow curve. This kind of chromatography determines the size of pores within the textile but gives little information on channels that conduct flow. Inverse gas chromatography [ 1 ] is a means of determining the structure features of the solid phase (polymer structure) by analyzing singularities in retention-temperature diagrams to elute solutes from a column.In earlier work on permeability [4], we fitted air flow/pressure drop data for a variety of textiles to power function curves for which the exponents had values between 0.5 and 1. Further, we found that the exponent was '/2 for test specimens having channels of uniform dimensions. Subsequent experiments on specimens having small uniform channels revealed that inflection points separated regions of constant slopes of 1 and 'h when plotted on log-log plots. Since the slope gives the exponent of the power function describing the flow/ pressure relationship, the abrupt change indicated a distinct change in the power requirements to increase the flow. A new theory for the origin of the observed slopes was based on the key assumption that the identifiable inflection point pressures were associated with the flow in the uniform channels becoming nonlinear at a universal critical shear stress. This assumption was based on the constancy of the shear stres...

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Section: B Values For Added Flowsmentioning

confidence: 92%

Section: B Values For Added Flowsmentioning

confidence: 99%

mentioning

confidence: 99%

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A New Method for Pore Structure Analysis Using Air Flow

Hassenboehler

1984

Textile Research Journal

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“…The principles upon which the mercury-intrusion method is based, the derivation of the distributionfunction equation, the general method of procedure, and the sources of error have been discussed in the literature [ l, 2,3] . The relationship between the radius, r, of a circular pore and the pressure, necessary to just force the mercury into the pore is expressed [4] by the equation U being the surface tension of mercury and 0 the contact angle.…”

Section: Pore-size Distribution In a Selected Series Of Closely Wovenmentioning

confidence: 99%

Pore-Size Distribution in a Selected Series of Closely Woven Fabrics

Honold

Skau

1951

Textile Research Journal

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“…Of particular interest is the work that has been done to explain the effect of fabric construction variables on permeability [ 5 ]. Although Wakeham and Spicer [35] showed a good correlation to exist between permeability and the interfiber and intrafiber voids of a tightly woven fabric, it is usually conceded that the porosity of an open-weave fabric is mainly dependent upon the interyarn pores. Many workers recognized that for fabrics of a given fiber, yarn diameter, and texture, the porosity to air and other fluids is further dependent upon the type of weave.…”

Section: Introductionmentioning

confidence: 99%

Flow Through Fabric-like Structures

Penner

Robertson

1951

Textile Research Journal

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A method is presented for the visual investigation of flow through fabrics. The fabric pores are considered as orifices, and the effect of weave structure on the fluid flow is investigated in the range of Reynold's numbers 10 to 400.For this investigation, a liquid is forced past models representing the four possible combinations of yarns in a woven fabric interstice, and the fluid motion is visualized by using air bubbles, which are detected by means of a suitable light source, as the distinguishing medium. Since both the fluid and the construction material for the models and viewing chamber are translucent and possess the same refractive indices, it is possible to obtain uninterrupted, undistorted visualization of the fluid flow through and past the fabric-like structures. Visual and photographic investigations of the flow are made in various significant planes normal to the fabric-like structures, or parallel to the direction of flow. The resulting photographs are analyzed and interpreted to provide information concerning the effect of fabric construction and variation of Reynold's number on the area available for the passage of fluids through each pore type, or the so-called "effective pore area."It is shown that the four pore types do not behave like geometrically similar orifices, so that for a given diameter/pitch ratio the effective pore area is not the same in all cases. This area decreases with increasing Reynold's number. Except at very low Reynold's numbers, the effective pore area proves to be less than the actual minimum pore area, but greater than the projected area, with the exception of the plain-weave pore type. Assuming a minimum crosssectional pore area, as determined by graphical analysis, it is shown that the effective pore area/minimum pore area ratio is almost a constant for all four pore types of the models tested at a Reynold's number of 400.

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Pore-Size Distribution in Textiles-A Study of Windproof and Water-Resistant Cotton Fabrics

Cited by 26 publications

References 4 publications

A New Method for Pore Structure Analysis Using Air Flow

A New Method for Pore Structure Analysis Using Air Flow

Pore-Size Distribution in a Selected Series of Closely Woven Fabrics

Flow Through Fabric-like Structures

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