| People | Locations | Statistics |
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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Ketoja, Jukka A.
VTT Technical Research Centre of Finland
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (17/17 displayed)
- 2022Lignin interdiffusion - a mechanism behind improved wet strength
- 2022Utilizing and Valorizing Oat and Barley Straw as an Alternative Source of Lignocellulosic Fiberscitations
- 2022Utilizing and Valorizing Oat and Barley Straw as an Alternative Source of Lignocellulosic Fiberscitations
- 2021General mean-field theory to predict stress-compression behaviour of lightweight fibrous materials
- 2020Crossover from mean-field compression to collective phenomena in low-density foam-formed fiber materialcitations
- 2018Foam-formed fibre materials
- 2018Effect of cellulosic fibers on foam dynamics
- 2017Novel biobased micro- and nanomaterials in porous foam formed structures
- 2017Design-driven integrated development of technical and perceptual qualities in foam-formed cellulose fibre materialscitations
- 2017Design-driven integrated development of technical and perceptual qualities in foam-formed cellulose fibre materialscitations
- 2016Tailoring the microporous structure of fibre materials with foam carrier
- 2016Porous structure of fibre networks formed by a foaming process: a comparative study of different characterization techniquescitations
- 2015The effect of physical adhesion promotion treatments on interfacial adhesion in cellulose-epoxy
- 2014Wet fibre-laden foams in axial mixing with macro-instabilities
- 2013Bubble size and air content of wet fibre foams in axial mixing with macro-instabilitiescitations
- 2009Wet Web Rheology on a Paper Machine
- 2008Simulation of triaxial deformation of wet fiber networkscitations
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document
Wet fibre-laden foams in axial mixing with macro-instabilities
Abstract
The air content and bubble size distribution in purefoams and in fibre foams were determined in axial mixingfor varied rotation speed, liquid surface tension andwood fibre consistency. Onset of flow macro-instabilitieswere observed at high rotation speeds both with andwithout fibres. Before the instability, the bubble sizedecreased and air content increased with increasingrotation speed. After the instability, the air contentwas not only strongly affected by rotation speed but,interestingly, both the air content and bubble sizeincreased with reduced surface tension. In both regions,the average bubble size could be explained based on thecapillary number after the air content was explicitlyincluded in the model. With kraft fibres included in thefoam, the behaviour of the air content is very similar tothat without fibres but the macro-instability behaviourbegins a bit earlier, roughly at N=5000 RPM for thesurfactant concentration of 0.2 g/l. At this rotationspeed, the air content finds its maximum for both 0.33and 0.66% consistency.The main effect of the fibres is to reduce the bubblesize in the stable region. The higher the consistency offibres, the greater the reduction in the mean radiusturns out to be. This is probably due to the added localshear forces due to fibre inertia enhancing the breakingtendency of the larger bubbles. However, it seems that inthe unstable regime the fibres do not have a similareffect. For very high rotation speeds, the bubble size ispractically equivalent with and without fibres. Thismight be caused by the change in the turbulence spectrumat the beginning of instabilities - the shear forces dueto the fluid phase may become strong enough to dominatethose caused by the fibre inertia.