Pipe rheology of microfibrillated cellulose suspensions

Tuomas Turpeinen, Ari Jäsberg, Sanna Haavisto, Johanna Liukkonen, Juha Salmela, Antti Koponen (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

Abstract

The shear rheology of two mechanically manufactured microfibrillated cellulose (MFC) suspensions was studied in a consistency range of 0.2 - 2.0% with a pipe rheometer combined with ultrasound velocity profiling. The MFC suspensions behaved at all consistencies as shear thinning power law fluids. Despite their significantly different particle size, the viscous behavior of the suspensions was quantitatively similar. For both suspensions, the dependence of yield stress and the consistency index on consistency was a power law with an exponent of 2.4, similar to some pulp suspensions. The dependence of flow index on consistency was also a power law, with an exponent of -0.36. The slip flow was very strong for both MFCs and contributed up to 95% to the flow rate. When wall shear stress exceeded two times the yield stress, slip flow caused drag reduction with consistencies higher than 0.8%. When inspecting the slip velocities of both suspensions as a function of wall shear stress scaled with the yield stress, a good data collapse was obtained. The observed similarities in the shear rheology of both the MFC suspensions and the similar behavior of some pulp fiber suspensions suggests that the shear rheology of MFC suspensions might be more universal than has previously been realized.
Original languageEnglish
Number of pages16
JournalCellulose
Publication statusE-pub ahead of print - 19 Oct 2019
MoE publication typeA1 Journal article-refereed

Fingerprint

Rheology
Cellulose
Suspensions
Pipe
Yield stress
Pulp
Shear stress
Drag reduction
Shear thinning
Rheometers
Ultrasonics
Particle size
Flow rate
Fluids
Fibers

Keywords

  • velocity profile
  • ultrasound velocity profiling
  • microfibrillated cellulose
  • rheology
  • yild stress
  • viscosity
  • shear thinning
  • slip flow

Cite this

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title = "Pipe rheology of microfibrillated cellulose suspensions",
abstract = "The shear rheology of two mechanically manufactured microfibrillated cellulose (MFC) suspensions was studied in a consistency range of 0.2 - 2.0{\%} with a pipe rheometer combined with ultrasound velocity profiling. The MFC suspensions behaved at all consistencies as shear thinning power law fluids. Despite their significantly different particle size, the viscous behavior of the suspensions was quantitatively similar. For both suspensions, the dependence of yield stress and the consistency index on consistency was a power law with an exponent of 2.4, similar to some pulp suspensions. The dependence of flow index on consistency was also a power law, with an exponent of -0.36. The slip flow was very strong for both MFCs and contributed up to 95{\%} to the flow rate. When wall shear stress exceeded two times the yield stress, slip flow caused drag reduction with consistencies higher than 0.8{\%}. When inspecting the slip velocities of both suspensions as a function of wall shear stress scaled with the yield stress, a good data collapse was obtained. The observed similarities in the shear rheology of both the MFC suspensions and the similar behavior of some pulp fiber suspensions suggests that the shear rheology of MFC suspensions might be more universal than has previously been realized.",
keywords = "velocity profile, ultrasound velocity profiling, microfibrillated cellulose, rheology, yild stress, viscosity, shear thinning, slip flow",
author = "Tuomas Turpeinen and Ari J{\"a}sberg and Sanna Haavisto and Johanna Liukkonen and Juha Salmela and Antti Koponen",
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year = "2019",
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language = "English",
journal = "Cellulose",
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Pipe rheology of microfibrillated cellulose suspensions. / Turpeinen, Tuomas; Jäsberg, Ari; Haavisto, Sanna; Liukkonen, Johanna; Salmela, Juha; Koponen, Antti (Corresponding Author).

In: Cellulose, 19.10.2019.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Pipe rheology of microfibrillated cellulose suspensions

AU - Turpeinen, Tuomas

AU - Jäsberg, Ari

AU - Haavisto, Sanna

AU - Liukkonen, Johanna

AU - Salmela, Juha

AU - Koponen, Antti

N1 - FLIPT project?

PY - 2019/10/19

Y1 - 2019/10/19

N2 - The shear rheology of two mechanically manufactured microfibrillated cellulose (MFC) suspensions was studied in a consistency range of 0.2 - 2.0% with a pipe rheometer combined with ultrasound velocity profiling. The MFC suspensions behaved at all consistencies as shear thinning power law fluids. Despite their significantly different particle size, the viscous behavior of the suspensions was quantitatively similar. For both suspensions, the dependence of yield stress and the consistency index on consistency was a power law with an exponent of 2.4, similar to some pulp suspensions. The dependence of flow index on consistency was also a power law, with an exponent of -0.36. The slip flow was very strong for both MFCs and contributed up to 95% to the flow rate. When wall shear stress exceeded two times the yield stress, slip flow caused drag reduction with consistencies higher than 0.8%. When inspecting the slip velocities of both suspensions as a function of wall shear stress scaled with the yield stress, a good data collapse was obtained. The observed similarities in the shear rheology of both the MFC suspensions and the similar behavior of some pulp fiber suspensions suggests that the shear rheology of MFC suspensions might be more universal than has previously been realized.

AB - The shear rheology of two mechanically manufactured microfibrillated cellulose (MFC) suspensions was studied in a consistency range of 0.2 - 2.0% with a pipe rheometer combined with ultrasound velocity profiling. The MFC suspensions behaved at all consistencies as shear thinning power law fluids. Despite their significantly different particle size, the viscous behavior of the suspensions was quantitatively similar. For both suspensions, the dependence of yield stress and the consistency index on consistency was a power law with an exponent of 2.4, similar to some pulp suspensions. The dependence of flow index on consistency was also a power law, with an exponent of -0.36. The slip flow was very strong for both MFCs and contributed up to 95% to the flow rate. When wall shear stress exceeded two times the yield stress, slip flow caused drag reduction with consistencies higher than 0.8%. When inspecting the slip velocities of both suspensions as a function of wall shear stress scaled with the yield stress, a good data collapse was obtained. The observed similarities in the shear rheology of both the MFC suspensions and the similar behavior of some pulp fiber suspensions suggests that the shear rheology of MFC suspensions might be more universal than has previously been realized.

KW - velocity profile

KW - ultrasound velocity profiling

KW - microfibrillated cellulose

KW - rheology

KW - yild stress

KW - viscosity

KW - shear thinning

KW - slip flow

UR - https://doi.org/10.1007/s10570-019-02784-4

M3 - Article

JO - Cellulose

JF - Cellulose

SN - 0969-0239

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