Paper Number
PO34
Session
Poster Session
Title
Effects of spreading and geometry on capillary-driven thinning of viscous fluids
Presentation Date and Time
October 12, 2022 (Wednesday) 6:30
Track / Room
Poster Session / Riverwalk A
Authors
- Zhang, Diana Y. (University of Minnesota, Chemical Engineering and Materials Science)
- Lauser, Kathleen T. (University of Minnesota, Chemical Engineering and Materials Science)
- Luong, Romy (University of Minnesota, Chemical Engineering and Materials Science)
- Robertson, Ben P. (University of Minnesota, Chemical Engineering and Materials Science)
- Calabrese, Michelle A. (University of Minnesota, Chemical Engineering and Materials Science)
Author and Affiliation Lines
Diana Y. Zhang, Kathleen T. Lauser, Romy Luong, Ben P. Robertson and Michelle A. Calabrese
Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455
Speaker / Presenter
Zhang, Diana Y.
Keywords
experimental methods; rheometry techniques
Text of Abstract
In dripping-onto-substrate (DoS) extensional rheometry, achieving an optimal degree of spreading of the fluid on the substrate is instrumental to unstable liquid bridge formation and subsequent thinning. Prior work in the literature has shown that for microstructured fluids, the moving contact line in DoS experiments can yield different extensional rheological parameters than experiments in which the contact line is pinned. However, these measurements did not consider the relation between liquid bridge stability and droplet spreading in the analysis. Moreover, the impact of droplet spreading on capillary-driven thinning measurements of “simpler” Newtonian fluids has not yet been systematically studied, and no attempts have been made to explicitly define the optimal operating window. In this work, the effects of a moving contact line, inherent to the traditional DoS method but absent in the CaBER method, on the capillary-driven thinning of a liquid bridge is systematically explored. Extensional rheology parameters such as breakup time, power law index, and shear viscosity determined from CaBER measurements are compared to those from unpinned and pinned DoS measurements of a model viscous oil. Additionally, differences in CaBER and DoS extensional rheology are analyzed in terms of volume fill fraction and liquid bridge stability. Results highlight important spreading considerations in DoS measurements and inform both DoS and CaBER users on the extent of the impact droplet spreading has on Newtonian fluid extensional rheology.