Response of wet foam to fibre mixing

A.M. Al-Qararah, T. Hjelt, A. Koponen, A. Harlin, Jukka Ketoja (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

8 Citations (Scopus)

Abstract

Air content and bubble size are the key parameters in describing aqueous wet foam. These two parameters respond differently to added fibres in axially agitated mixing. Both air content and bubble size depend on the process characteristics such as mixing geometry, rotation speed and surface tension. However, for moderate rotation speeds, air content is rather insensitive to the added cellulose-based fibres, whereas the mean bubble size varies strongly with the fibre type. Even though the bubble size is usually reduced by the added fibres, short fibres can also increase the bubble size. The mean bubble size clearly becomes smaller for wood fibres than for viscose fibres even if these two types of fibres have similar geometric dimensions. Moreover, the bubble size distribution becomes narrower with wood fibres. This suggests a bubble breaking mechanism induced both by the rough surfaces of wood fibres and by the associated fine particle fraction that are both absent with smooth viscose fibres. At high rotation speeds, the air content becomes extremely sensitive to the fibres due to macro-instabilities causing an irregular flow of the wet foam.
Original languageEnglish
Pages (from-to)97-106
JournalColloids and Surfaces A: Physicochemical and Engineering Aspects
Volume467
DOIs
Publication statusPublished - 2015
MoE publication typeA1 Journal article-refereed

Fingerprint

foams
Foams
fibers
Fibers
bubbles
Wood
Air
air
Cellulose
Macros
Surface tension
cellulose
interfacial tension
Geometry

Keywords

  • wood
  • bubble columns
  • fibers
  • mixing
  • wet foams

Cite this

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title = "Response of wet foam to fibre mixing",
abstract = "Air content and bubble size are the key parameters in describing aqueous wet foam. These two parameters respond differently to added fibres in axially agitated mixing. Both air content and bubble size depend on the process characteristics such as mixing geometry, rotation speed and surface tension. However, for moderate rotation speeds, air content is rather insensitive to the added cellulose-based fibres, whereas the mean bubble size varies strongly with the fibre type. Even though the bubble size is usually reduced by the added fibres, short fibres can also increase the bubble size. The mean bubble size clearly becomes smaller for wood fibres than for viscose fibres even if these two types of fibres have similar geometric dimensions. Moreover, the bubble size distribution becomes narrower with wood fibres. This suggests a bubble breaking mechanism induced both by the rough surfaces of wood fibres and by the associated fine particle fraction that are both absent with smooth viscose fibres. At high rotation speeds, the air content becomes extremely sensitive to the fibres due to macro-instabilities causing an irregular flow of the wet foam.",
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Response of wet foam to fibre mixing. / Al-Qararah, A.M.; Hjelt, T.; Koponen, A.; Harlin, A.; Ketoja, Jukka (Corresponding Author).

In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, Vol. 467, 2015, p. 97-106.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Response of wet foam to fibre mixing

AU - Al-Qararah, A.M.

AU - Hjelt, T.

AU - Koponen, A.

AU - Harlin, A.

AU - Ketoja, Jukka

PY - 2015

Y1 - 2015

N2 - Air content and bubble size are the key parameters in describing aqueous wet foam. These two parameters respond differently to added fibres in axially agitated mixing. Both air content and bubble size depend on the process characteristics such as mixing geometry, rotation speed and surface tension. However, for moderate rotation speeds, air content is rather insensitive to the added cellulose-based fibres, whereas the mean bubble size varies strongly with the fibre type. Even though the bubble size is usually reduced by the added fibres, short fibres can also increase the bubble size. The mean bubble size clearly becomes smaller for wood fibres than for viscose fibres even if these two types of fibres have similar geometric dimensions. Moreover, the bubble size distribution becomes narrower with wood fibres. This suggests a bubble breaking mechanism induced both by the rough surfaces of wood fibres and by the associated fine particle fraction that are both absent with smooth viscose fibres. At high rotation speeds, the air content becomes extremely sensitive to the fibres due to macro-instabilities causing an irregular flow of the wet foam.

AB - Air content and bubble size are the key parameters in describing aqueous wet foam. These two parameters respond differently to added fibres in axially agitated mixing. Both air content and bubble size depend on the process characteristics such as mixing geometry, rotation speed and surface tension. However, for moderate rotation speeds, air content is rather insensitive to the added cellulose-based fibres, whereas the mean bubble size varies strongly with the fibre type. Even though the bubble size is usually reduced by the added fibres, short fibres can also increase the bubble size. The mean bubble size clearly becomes smaller for wood fibres than for viscose fibres even if these two types of fibres have similar geometric dimensions. Moreover, the bubble size distribution becomes narrower with wood fibres. This suggests a bubble breaking mechanism induced both by the rough surfaces of wood fibres and by the associated fine particle fraction that are both absent with smooth viscose fibres. At high rotation speeds, the air content becomes extremely sensitive to the fibres due to macro-instabilities causing an irregular flow of the wet foam.

KW - wood

KW - bubble columns

KW - fibers

KW - mixing

KW - wet foams

U2 - 10.1016/j.colsurfa.2014.11.034

DO - 10.1016/j.colsurfa.2014.11.034

M3 - Article

VL - 467

SP - 97

EP - 106

JO - Colloids and Surfaces A: Physicochemical and Engineering Aspects

JF - Colloids and Surfaces A: Physicochemical and Engineering Aspects

SN - 0927-7757

ER -