Application of Doppler Optical Coherence Tomography in Velocity Profiling Rheometry of Complex Fluids
In this thesis, Doppler Optical Coherence Tomography (DOCT) was applied to velocity profiling rheometry in combination with rotational rheometer and pipe rheometer. In addition to the velocity profiling, the imaging modality of the OCT was utilized in characterizing the structural behavior of the materials under study. Furthermore, a novel hybrid multi-scale velocity profiling method, based on measuring stationary velocity profiles of fluid flow in a straight tube simultaneously by DOCT and ultrasound velocity profiling (UVP), was developed. The data from the two instruments can be combined into a comprehensive velocity profile including information on the thin boundary layer near the tube wall as measured by DOCT, and in the interior parts of the of flow as measured by UVP. The experimental methods were used to investigate the rheology of aqueous microfibrillated cellulose (MFC) suspensions, which show complex rheological properties. It was found that flow curve measurements with rotational rheometer and smooth concentric cylinders are greatly affected by shear localization effects. In particular, conventional analysis of the bulk properties of MFC suspensions at shear stress values below their yield stress did not appear appropriate – despite the seemingly reasonable power-law flow curves thereby obtained. Experiments with the pipe rheometer and hybrid multi-scale method showed that within the boundary layer concentration and thereby the viscosity of MFC decreases towards the wall. At high values of flow rate, sublayer of virtually pure water was observed next to the wall, giving rise to apparent wall slip. The results from the interior part of the flow showed shear-thinning behavior in qualitative agreement with results obtained by using conventional rheological methods. Velocity profiling rheometry with DOCT and hybrid multi-scale methods appear useful in analyzing the rheological behavior of complex fluids. They can provide detailed experimental information on the rheology of MFC suspensions and their intricate boundary layer flow behavior, avoiding uncertainties inherent in many conventional rheological techniques. ...
- Artikkeli I: Haavisto, S., Salmela, J., & Koponen, A. (2015). Accurate velocity measurements of boundary-layer flows using Doppler optical coherence tomography. Experiments in Fluids, 56 (5), 96. DOI: 10.1007/s00348-015-1962-2
- Artikkeli II: Haavisto, S., Salmela, J., Jasberg, A., Saarinen, T., Karppinen, A. & Koponen, A. (2015). Rheological characterization of microfibrillated cellulose suspension using Optical Coherence Tomography. Tappi Journal 14 (5), 291-302.
- Artikkeli III: Saarinen T, Haavisto S, Sorvari A, Salmela J, Seppälä J. (2014) The effect of wall depletion on the rheology of microfibrillated cellulose water suspensions by optical coherence tomography. Cellulose. 21(3), 1261-75. DOI: 10.1007/s10570‐014‐0187‐5
- Artikkeli IV: Kataja, M., Haavisto, S., Salmela, J., Lehto, R., & Koponen, A. (2017). Characterization of micro-fibrillated cellulose fiber suspension flow using multi scale velocity profile measurements. Nordic Pulp and Paper Research Journal, 32 (3), 473-482. DOI: 10.3183/NPPRJ-2017-32-03-p473-482
MetadataShow full item record
Showing items with similar title or keywords.
Abel transforms with low regularity with applications to x-ray tomography on spherically symmetric manifolds Hoop, Maarten V de; Ilmavirta, Joonas (Institute of Physics, 2017)We study ray transforms on spherically symmetric manifolds with a piecewise C 1,1 metric. Assuming the Herglotz condition, the X-ray transform is injective on the space of L 2 functions on such manifolds. We also prove ...
Tracer migration in crystalline rock : application to geological barriers of nuclear waste storage Kuva, Jukka (University of Jyväskylä, 2016)This work deals with transport of radionuclides in the geosphere. The subject is investigated through characterisation of water conducting fractures, determining of rock transport properties and development of new methods ...
The nature of security and risk in complex socio-technical systems : a partial application of Critical Systems Heuristics (CSH) to Finnish Security Strategy for Society (YTS) Reivo, Juho (2011)Tämä tutkimus selventää suhteita turvallisuuden, riskien sekä kompleksisten sosio-teknisten järjestelmien välillä. Käsittely tapahtuu pääosin yhteiskunnallisella tasolla, mutta eri järjestelmiä ja niiden yleisiä sekä ...
Model order effects on ICA of resting-state complex-valued fMRI data : application to schizophrenia Kuang, Li-Dan; Lin, Qiu-Hua; Gong, Xiao-Feng; Cong, Fengyu; Sui, Jing; Calhoun, Vince D. (Elsevier BV, 2018)Background Component splitting at higher model orders is a widely accepted finding for independent component analysis (ICA) of functional magnetic resonance imaging (fMRI) data. However, our recent study found that intact ...
FPI Based Hyperspectral Imager for the Complex Surfaces : Calibration, Illumination and Applications Raita-Hakola, Anna-Maria; Annala, Leevi; Lindholm, Vivian; Trops, Roberts; Näsilä, Antti; Saari, Heikki; Ranki, Annamari; Pölönen, Ilkka (MDPI AG, 2022)Hyperspectral imaging (HSI) applications for biomedical imaging and dermatological applications have been recently under research interest. Medical HSI applications are non-invasive methods with high spatial and spectral ...