miun.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Simulation of the motion of flexible fibres in viscous fluid flow
Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
Responsible organisation
2007 (English)In: Physics of fluids, ISSN 1070-6631, E-ISSN 1089-7666, Vol. 19, no 11, 113307Article in journal (Refereed) Published
Abstract [en]

A model for flexible fibers in viscous fluid flow is proposed, and its predictions compared with experiments found in the literature. The incompressible three-dimensional Navier-Stokes equations are employed to describe the fluid motion, while fibers are modeled as chains of fiber segments, interacting with the fluid through viscous and dynamic drag forces. Fiber segments, from the same or from different fibers, interact with each other through normal, frictional and lubrication forces. Momentum conservation is enforced on the system to capture the two-way coupling between phases. Quantitative predictions could be made, and showed good agreement with experimental data, for the period time of Jeffery orbits in shear flow, as well as for the amount of bending of flexible fibers in shear flow. Simulations, using the proposed model, also successfully reproduced the different regimes of motion for threadlike particles, ranging from rigid fiber motion to complicated orbiting behavior, including coiling and self-entanglement.

Place, publisher, year, edition, pages
2007. Vol. 19, no 11, 113307
Keyword [en]
fiber, fluid flow, fiber suspension, fiber flexibility, simulation
National Category
Other Engineering and Technologies Chemical Engineering
Identifiers
URN: urn:nbn:se:miun:diva-412DOI: 10.1063/1.2778937ISI: 000251325700018Scopus ID: 2-s2.0-36849039349Local ID: 5051OAI: oai:DiVA.org:miun-412DiVA: diva2:2039
Projects
Stochastic Modelling of Paper Structures
Available from: 2008-11-20 Created: 2008-11-13 Last updated: 2016-09-26Bibliographically approved
In thesis
1. Modelling and simulation of paper structure development
Open this publication in new window or tab >>Modelling and simulation of paper structure development
2008 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

 

 

 

 

 

A numerical tool has been developed for particle-level simulations of fibre suspension flows, particularly forming of the fibre network structure of paper sheets in the paper machine. The model considers inert fibres of various equilibrium shapes, and finite stiffness, interacting with each other through normal, frictional, and lubrication forces, and with the surrounding fluid medium through hydrodynamic forces. Fibre–fluid interactions in the non-creeping flow regime are taken into account, and the two-way coupling between the solids and the fluid phases is included by enforcing momentum conservation between phases. The incompressible three-dimensional Navier–Stokes equations are employed tomodel themotion of the fluid medium.

The validity of the model has been tested by comparing simulation results with experimental data from the literature. It was demonstrated that the model predicts well the motion of isolated fibres in shear flow over a wide range of fibre flexibilities. It was also shown that the model predicts details of the orientation distribution of

 

multiple, straight, rigid fibres in a sheared suspension. Furthermore, model predictions of the shear viscosity and first normal stress difference were in fair agreement with experimental data found in the literature. Since the model is based solely on first principles physics, quantitative predictions could be made without any parameter fitting.

 

Based on these validations, a series of simulations have been performed to investigate the basic mechanisms responsible for the development of the stress tensor components for monodispersed, non-Brownian fibres suspended in a Newtonian fluid in shear flow. The effects of fibre aspect ratio, concentration, and inter-particle friction, as well as the tendency of fibre agglomeration, were examined in the nonconcentrated regimes. For the case of well dispersed suspensions, semi-empirical relationships were found between the aforementioned fibre suspension properties, and the steady state apparent shear viscosity, and the first/second normal stress differences.

 

Finally, simulations have been conducted for the development of paper structures in the forming section of the paper machine. The conditions used for the simulations were retrieved from pilot-scale forming trial data in the literature, and from real pulp fibre analyses. Dewatering was simulated by moving two forming fabrics toward each other through a fibre suspension. Effects of the jet-to-wire speed difference on the fibre orientation anisotropy, the mass density distribution, and three-dimensionality of the fibre network, were investigated. Simulation results showed that the model captures well the essential features of the forming effects on these paper structure parameters, and also posed newquestions on the conventional wisdom of the forming mechanics.

 

 

Place, publisher, year, edition, pages
Sundsvall: Department of Natural Sciences, Engineering and Mathematics, Mid Sweden University, 2008. 64 p.
Series
Mid Sweden University doctoral thesis, ISSN 1652-893X ; 60
Keyword
Forming, Fibre, Paper, Fibre suspension, Paper structure, Simulation, Rheology
National Category
Chemical Engineering Other Engineering and Technologies
Identifiers
urn:nbn:se:miun:diva-7003 (URN)978-91-86073-10-7 (ISBN)
Public defence
2008-10-28, O102, Mid Sweden University, Holmgatan 10, Sundsvall, 09:30 (English)
Opponent
Supervisors
Available from: 2008-11-12 Created: 2008-11-12 Last updated: 2009-03-19Bibliographically approved
2. Simulations of the Dynamics of Fibre Suspension Flows
Open this publication in new window or tab >>Simulations of the Dynamics of Fibre Suspension Flows
2007 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

A new model for simulating non-Brownian flexible fibres suspended in a Newtonian fluid has been developed. Special attention has been given to include realistic flow conditions found in the industrial papermaking process in the key features of the model; it is the intention of the author to employ the model in simulations of the forming section of the paper machine in future studies.

The model considers inert fibres of various shapes and finite stiffness, interacting with each other through normal, frictional and lubrication forces, and with the surrounding fluid medium through hydrodynamic forces. Fibre-fluid interactions in the non-creeping flow regime are taken into account, and the two-way coupling between the solids and the fluid phase is included by enforcing momentum conservation between phases. The incompressible three-dimensional Navier-Stokes equations are employed to model the motion of the fluid medium.

The validity of the model has been tested by comparing simulation results with experimental data from the literature. It was demonstrated that the model predicts the motion of isolated fibres in shear flow over a wide range of fibre flexibilities. It was also shown that the model predicts details of the orientation distribution of multiple straight, rigid fibres in a sheared suspension. Model predictions of the viscosity and first normal stress difference were in good agreement with experimental data found in the literature. Since the model is based solely on first-principles physics, quantitative predictions could be made without any parameter fitting.

Abstract [sv]

En ny modell för simulering av rörelserna hos icke-Brownska böjliga fibrer dispergerade i en Newtonsk vätska har utvecklats. Eftersom det är författarens avsikt att modellen skall kunna tillämpas vid simulering av arkformning under de förhållanden som råder i en modern pappersmaskin, har särskilt omsorg givits till att inkludera motsvarande flödesvillkor i modellens giltighetsområde.

Modellen hanterar fibrer av varierande form, massa och styvhet, som växelverkar sinsemellan via normal-, friktions- och smörjkrafter. Deras växelverkan med den omgivande vätskan sker via hydrodynamiska krafter vid finita Reynolds-tal. Den så kallade tvåvägskopplingen mellan fibrerna och vätskefasen har tagits i beaktande genom att kräva att rörelsemängden bevaras vid interaktionen mellan faserna. Vidare har Navier-Stokes ekvationer för inkompressibla vätskor använts för att beskriva mediets rörelser.

Modellens giltighet har undersökts genom att jämföra resultat från simuleringar med experimentella data från litteraturen. Det har påvisats att modellen förutsäger rörelsen hos ensamma fibrer i ett skjuvflöde, för vitt skilda fiberflexibiliteter. Det visades också att modellen förutsäger detaljer hos fiberorienteringsdistributionen i suspensioner utsatta för skjuvflöde. Det kunde också konstateras att modellens förutsägelser av fibersuspensioners viskositet och första normalspänningsdifferens under skjuvning väl överensstämde med experimentella data i litteraturen. Kvantitativa förutsägelser har kunnat göras utan någon parameteranpassning, då modellen bygger uteslutande på väletablerade fysikaliska samband inom klassisk mekanik och strömningslära.

Place, publisher, year, edition, pages
Sundsvall: Mid Sweden University, 2007
Series
Mid Sweden University licentiate thesis, ISSN 1652-8948 ; 25
Keyword
fibre, fibre suspension, simulation, paper, papermaking, forming, fibre orientation distribution, fibre flexibility, viscosity, first normal stress difference, fluid flow, simple shear flow, two-way coupling, three-dimensional
National Category
Chemical Engineering Other Engineering and Technologies
Identifiers
urn:nbn:se:miun:diva-53 (URN)5137 (Local ID)978-91-85317-62-2 (ISBN)5137 (Archive number)5137 (OAI)
Presentation
2007-09-19, O102, O-huset, Holmgatan 10, Sundsvall, 10:00 (English)
Opponent
Supervisors
Available from: 2008-01-07 Created: 2008-01-07 Last updated: 2009-07-10Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopushttp://link.aip.org/link/?PHF/19/113307

Search in DiVA

By author/editor
Lindström, StefanUesaka, Tetsu
By organisation
Department of Natural Sciences
In the same journal
Physics of fluids
Other Engineering and TechnologiesChemical Engineering

Search outside of DiVA

GoogleGoogle Scholar

Altmetric score

Total: 1132 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf