6533b830fe1ef96bd1297a81
RESEARCH PRODUCT
Online measurement of floc size, viscosity, and consistency of cellulose microfibril suspensions with optical coherence tomography
Tapio FabritiusJuha SalmelaArttu MiettinenJanne LauriSanna HaavistoAntti Koponensubject
Materials sciencePolymers and Plasticsselluloosa02 engineering and technology01 natural sciences010309 opticsViscositysuspensiotConsistency (statistics)flocculationreologia0103 physical sciencesShear stressCMFComposite materialSuspension (vehicle)Pressure dropShear thinningoptical coherence tomographyconsistencymikrokuidutviskositeettioptinen koherenssitomografia021001 nanoscience & nanotechnologyfloc sizeCellulose microfibrilcellulose microfibrilsOCTAttenuation coefficientviscosityrheology0210 nano-technologydescription
AbstractIn this study, cellulose microfibril (CMF) suspensions were imaged during pipe flow at consistencies of 0.4%, 1.0%, and 1.6% with optical coherence tomography (OCT) to obtain images of the structure and the local velocity of the suspension. The viscosities obtained by combining pressure loss measurement with the OCT velocity data showed typical shear thinning behavior and were in excellent agreement with viscosities obtained with ultrasound velocity profiling. The structural OCT images were used to calculate the radial and the axial floc sizes of the suspension. A fit of power law to the geometrical floc size–shear stress data gave the same power law index for all consistencies, suggesting that floc rupture dynamics is independent of consistency. The dependence of viscosity and floc size on shear stress was similar, indicating that the shear thinning behavior of CMF suspensions is closely related to the rupture dynamics of flocs. The results also showed that an apparent attenuation coefficient of the OCT signal can be used to determine the consistency of CMF suspensions.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2021-04-01 |