Wet fibre-laden foams in axial mixing with macro-instabilities

Research output: Contribution to conferenceConference PosterScientific

Abstract

Wet foam is an excellent carrier phase to produce particle or fibre structures. Thus, it is important to know how particles or fibres affect foam properties. We study foams generated by axially agitated mixing with 60-80% air content. The shear rate and resulting capillary number in mixing are very high compared to similar parameters in typical foam rheology studies. Onset of a flow macro-instability is observed at high rotation speeds both with and without cellulose fibres. The air content of the foam is strongly affected by this instability. By describing the effect of the air content on the stability of bubble interfaces, we explain the bubble size for broad ranges of rotation speed and surface tension. Added fibres usually reduce the bubble size for a fixed rotation speed. After the flow macro-instability, not only the air content but also the bubble size increases with reduced surface tension. Beyond the instability, the effect of fibres on foam properties becomes minor.
Original languageEnglish
Publication statusPublished - 2014
Event9th Annual European Rheology Conference, AERC 2014 - Karlsruhe, Germany
Duration: 8 Apr 201411 Apr 2014

Conference

Conference9th Annual European Rheology Conference, AERC 2014
Abbreviated titleAERC
CountryGermany
CityKarlsruhe
Period8/04/1411/04/14

Fingerprint

foams
fibers
bubbles
air
interfacial tension
cellulose
rheology
shear

Keywords

  • foam
  • fibre
  • mixing
  • air content
  • bubble size
  • flow

Cite this

Ketoja, J., Al-Qararah, A., Hjelt, T., Koponen, A., & Harlin, A. (2014). Wet fibre-laden foams in axial mixing with macro-instabilities. Poster session presented at 9th Annual European Rheology Conference, AERC 2014, Karlsruhe, Germany.
Ketoja, Jukka ; Al-Qararah, Ahmad ; Hjelt, Tuomo ; Koponen, Antti ; Harlin, Ali. / Wet fibre-laden foams in axial mixing with macro-instabilities. Poster session presented at 9th Annual European Rheology Conference, AERC 2014, Karlsruhe, Germany.
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abstract = "Wet foam is an excellent carrier phase to produce particle or fibre structures. Thus, it is important to know how particles or fibres affect foam properties. We study foams generated by axially agitated mixing with 60-80{\%} air content. The shear rate and resulting capillary number in mixing are very high compared to similar parameters in typical foam rheology studies. Onset of a flow macro-instability is observed at high rotation speeds both with and without cellulose fibres. The air content of the foam is strongly affected by this instability. By describing the effect of the air content on the stability of bubble interfaces, we explain the bubble size for broad ranges of rotation speed and surface tension. Added fibres usually reduce the bubble size for a fixed rotation speed. After the flow macro-instability, not only the air content but also the bubble size increases with reduced surface tension. Beyond the instability, the effect of fibres on foam properties becomes minor.",
keywords = "foam, fibre, mixing, air content, bubble size, flow",
author = "Jukka Ketoja and Ahmad Al-Qararah and Tuomo Hjelt and Antti Koponen and Ali Harlin",
note = "HUO: Poster presentation CA2: BA3152 CA2: BA3151 CA2: BA313 Project code: 79606; 9th Annual European Rheology Conference, AERC 2014, AERC ; Conference date: 08-04-2014 Through 11-04-2014",
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Ketoja, J, Al-Qararah, A, Hjelt, T, Koponen, A & Harlin, A 2014, 'Wet fibre-laden foams in axial mixing with macro-instabilities' 9th Annual European Rheology Conference, AERC 2014, Karlsruhe, Germany, 8/04/14 - 11/04/14, .

Wet fibre-laden foams in axial mixing with macro-instabilities. / Ketoja, Jukka; Al-Qararah, Ahmad; Hjelt, Tuomo; Koponen, Antti; Harlin, Ali.

2014. Poster session presented at 9th Annual European Rheology Conference, AERC 2014, Karlsruhe, Germany.

Research output: Contribution to conferenceConference PosterScientific

TY - CONF

T1 - Wet fibre-laden foams in axial mixing with macro-instabilities

AU - Ketoja, Jukka

AU - Al-Qararah, Ahmad

AU - Hjelt, Tuomo

AU - Koponen, Antti

AU - Harlin, Ali

N1 - HUO: Poster presentation CA2: BA3152 CA2: BA3151 CA2: BA313 Project code: 79606

PY - 2014

Y1 - 2014

N2 - Wet foam is an excellent carrier phase to produce particle or fibre structures. Thus, it is important to know how particles or fibres affect foam properties. We study foams generated by axially agitated mixing with 60-80% air content. The shear rate and resulting capillary number in mixing are very high compared to similar parameters in typical foam rheology studies. Onset of a flow macro-instability is observed at high rotation speeds both with and without cellulose fibres. The air content of the foam is strongly affected by this instability. By describing the effect of the air content on the stability of bubble interfaces, we explain the bubble size for broad ranges of rotation speed and surface tension. Added fibres usually reduce the bubble size for a fixed rotation speed. After the flow macro-instability, not only the air content but also the bubble size increases with reduced surface tension. Beyond the instability, the effect of fibres on foam properties becomes minor.

AB - Wet foam is an excellent carrier phase to produce particle or fibre structures. Thus, it is important to know how particles or fibres affect foam properties. We study foams generated by axially agitated mixing with 60-80% air content. The shear rate and resulting capillary number in mixing are very high compared to similar parameters in typical foam rheology studies. Onset of a flow macro-instability is observed at high rotation speeds both with and without cellulose fibres. The air content of the foam is strongly affected by this instability. By describing the effect of the air content on the stability of bubble interfaces, we explain the bubble size for broad ranges of rotation speed and surface tension. Added fibres usually reduce the bubble size for a fixed rotation speed. After the flow macro-instability, not only the air content but also the bubble size increases with reduced surface tension. Beyond the instability, the effect of fibres on foam properties becomes minor.

KW - foam

KW - fibre

KW - mixing

KW - air content

KW - bubble size

KW - flow

M3 - Conference Poster

ER -

Ketoja J, Al-Qararah A, Hjelt T, Koponen A, Harlin A. Wet fibre-laden foams in axial mixing with macro-instabilities. 2014. Poster session presented at 9th Annual European Rheology Conference, AERC 2014, Karlsruhe, Germany.