Surface Fracture in Axisymmetric Paste Extrusion

Domanti, A.T.J.; Bridgwater, J.

doi:10.1205/026387600526898

Cited by 21 publications

(13 citation statements)

References 7 publications

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“…(7). In this case, the yield stress is not included in the viscosity dependence, but is instead implemented through the von Mises criterion imposed on the elastic stress.…”

Section: Models/formulationmentioning

confidence: 99%

“…They typically display non-Newtonian behavior, can be prone to phase migration [4], can exhibit thixotropic tendencies [5] and often include large particulates such as sand or other, smaller particulates [6]. The extrusion process itself adds an additional complication to matters with various forms of surface fractures [7], knots, accumulations, and tears. These instabilities are sometimes even encouraged, adding texture and increased surface area to the final product.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The extrusion of a model yield stress fluid imaged by MRI velocimetry

Rabideau¹,

Moucheront²,

Bertrand³

et al. 2010

Journal of Non-Newtonian Fluid Mechanics

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“…(7). In this case, the yield stress is not included in the viscosity dependence, but is instead implemented through the von Mises criterion imposed on the elastic stress.…”

Section: Models/formulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The extrusion of a model yield stress fluid imaged by MRI velocimetry

Rabideau¹,

Moucheront²,

Bertrand³

et al. 2010

Journal of Non-Newtonian Fluid Mechanics

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“…It is an interesting candidate for a material which could display either solid-like slip (normal stress-dependent, velocity-independent) or liquid-like slip as described above (normal stress-independent, velocity-dependent). Extrusion of soap materials has been studied previously, for example by Amarasinghe and Wilson (1998), Domanti and Bridgwater (2000), Kalyon et al (2004) and Barnes et al (2006), where soaps were found to be reproducible and reliable extrusion materials with behaviour conforming to the Benbow and Bridgwater (1993) model for extrusion. It is important to distinguish between solid soap as studied here, consisting of pure stearates with minimal water content, from bar soaps or soaps containing fragrances or softeners (often oil-based), such as those studied by Kalyon et al (2004) and Barnes et al (2006), which have additional liquid content and as such flow more readily.…”

Section: Introductionmentioning

confidence: 99%

Measurement of the wall slip behaviour of a solid granular soap in ram extrusion

2018

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The wall slip behaviour of a solid granular soap was investigated in the context of ram extrusion, with particular focus on determining the sensitivity of the wall shear stress to the pressure within the soap, as well as the slip velocity. Two novel slip measurement devices were used to infer the shear stress: a two stage extrusion die with inbuilt pressure gradient measurement; and a combined compression-translation assembly to measure the frictional force between the soap and the wall. Both devices provided differing measurements of the pressure sensitivity, and gave shear stress estimates in agreement with a Benbow and Bridgwater (1993) analysis of the extrusion behaviour, which cannot gauge pressure dependence. The influence of the wall material on the slip and extrusion behaviour was also investigated, using three geometrically identical extruders constructed from polycarbonate, stainless steel and tungsten carbide. There was found to be a non-negligible relationship between wall material, wall surface roughness, and the Benbow-Bridgwater extrusion parameters, in which the wall shear stress was greatest against the smoothest, cemented tungsten carbide wall in contrast to a rougher stainless steel and rougher-still polycarbonate wall.

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“…A dry, granular, solid soap used for commercial and domestic cleaning was selected as the experimental material. Soap extrusion has previously been studied by Amarasinghe and Wilson (1998), Domanti and Bridgwater (2000), Barnes et al (2006) and Castro et al (2010), and was found to behave reproducibly.…”

Section: Methodsmentioning

confidence: 98%

Flow visualisation and modelling of solid soap extrusion

Bryan

Rough

Wilson

2017

Chemical Engineering Science

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Ram extrusion of a solid granular soap was studied using three geometrically identical but differently-scaled extruders. The experimental design revealed deviation from the Benbow and Bridgwater (1993) extrusion model due to nonideal, scale-dependent effects. Typically these effects, linked to the shear rate in the extruder, are absorbed into the model's material pseudo-properties. The data were able to be represented using the Basterfield et al. (2005) model for extrusion flow which does include a shear rate as a variable. Flow visualisation in conjunction with fluid dynamics-based simulations showed, however, that the assumptions underlying the Basterfield et al. model are not appropriate for soap extrusion, despite the good agreement of the model with the experimental extrusion data. This highlights a need for care in interpretation of extrusion data, in that the limited information gathered about any given experiment, typically just the extrusion pressure, can lead to the generation of spurious parameters if the wrong model is applied.

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Surface Fracture in Axisymmetric Paste Extrusion

Cited by 21 publications

References 7 publications

The extrusion of a model yield stress fluid imaged by MRI velocimetry

The extrusion of a model yield stress fluid imaged by MRI velocimetry

Measurement of the wall slip behaviour of a solid granular soap in ram extrusion

Flow visualisation and modelling of solid soap extrusion

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