Paper Number
TM15 

Session
Rheometry: Advanced Techniques and Methods

Title
Transition criteria between scaling regimes in capillary thinning rheometry

Presentation Date and Time
October 22, 2019 (Tuesday) 9:50

Track / Room
Track 1 / Room 305A

Authors (Click on name to view author profile)

1. Clasen, Christian (KU Leuven, Department of Chemical Engineering)
2. Susanna, Formenti (KU Leuven)
3. Verbeke, Karel (KU Leuven)
4. Reddy, Naveen (Universiteit Hasselt, Faculty of Industrial Engineering)
5. Briatico-Vangosa, Francesco (Politecnico di Milano, Dipartimento di Chimica, Materiali e Ingegneria Chimica)
6. Anderson, Patrick D. (Eindhoven University of Technology, Mechanical Engineering, Polymer Technology Group)
7. Christos, Mitrias (TUe)

Author and Affiliation Lines (in printed abstract book)
Christian Clasen¹, Formenti Susanna¹, Karel Verbeke¹, Naveen Reddy², Francesco Briatico-Vangosa³, Patrick D. Anderson⁴, and Mitrias Christos^4
1Department of Chemical Engineering, KU Leuven, Leuven, Belgium; ²Faculty of Industrial Engineering, Universiteit Hasselt, Hasselt, Belgium; ³Dipartimento di Chimica, Materiali e Ingegneria Chimica, Politecnico di Milano, Milabo, Italy; ⁴Mechanical Engineering, Polymer Technology Group, Eindhoven University of Technology, Eindhoven, Noord-Brabant 5600 MB, The Netherlands

Speaker / Presenter 
Clasen, Christian

Text of Abstract
Capillary breakup extensional rheometry has proven to be a powerful tool for the investigation of extensional material functions of low viscous and weakly viscoelastic fluids. In particular the identification of scaling laws for the minimum filament diameter decay, when either viscosity, inertia, elasticity or combinations thereof dominate the fluid response, allows to fit the thinning profile in order to extract relaxation times of apparent extensional viscosities. One problem that arises, however, is the identification of the applicable scaling law for an observed filament thinning. This arises because the transition between scaling regimes is often broad, and different dominant material properties can lead to similar scaling laws that differ only in their respective coefficients, so that selection of the correct scaling law even in the absence of a transition can be ambiguous. In this paper we present therefore for the first time a two-dimensional map spanned by the Ohnesorge number Oh and the viscosity ratio p between the fluid viscosity and the viscosity of the outer medium, that allows to identify the filament diameters at the transitions between different thinning regime. We demonstrate that a quantitative description requires the incorporation of an additional dimensionless geometrical parameter that accounts for the critical axial and radial length scales of the filament. The validity of this map is demonstrated over six orders of magnitude for the Ohnesorge number, as well as nine orders of magnitude for the viscosity ratio, by experimental observation of filament thinning dynamics of model silicon oil and water/glycerol mixtures, as well as finite element numerical simulations for experimentally not accessible regimes.