Paper Number
NF24 

Session
Non-Newtonian Fluid Mechanics & Instabilities

Title
Quantitative predictions of the breakup times of inviscid-elastic filaments of dilute polymer solutions

Presentation Date and Time
February 16, 2017 (Thursday) 10:50

Track / Room
Track 2 / Audubon A

Authors (Click on name to view author profile)

1. Shahid, Taisir (KU Leuven, Department of Chemical Engineering)
2. Mathues, Wouter (KU Leuven, Department of Chemical Engineering)
3. Van Ruymbeke, Evelyne (Université catholique de Louvain, Bio and Soft Matter, Inst. on Cond. Matter and Nano-science)
4. Clasen, Christian (KU Leuven, Department of Chemical Engineering)

Author and Affiliation Lines (in printed abstract book)
Taisir Shahid¹, Wouter Mathues¹, Evelyne Van Ruymbeke², and Christian Clasen^1
1Department of Chemical Engineering, KU Leuven, Heverlee 3001, Belgium; ²Bio and Soft Matter, Inst. on Cond. Matter and Nano-science, Université catholique de Louvain, Louvain-la-Neuve B-1348, Belgium

Speaker / Presenter 
Clasen, Christian

Text of Abstract
The applicability of dilute polymer solutions in free surface flow processes that involve a strong extensional component depends to a large extend on the longevity of the filament that forms after the development of a Rayleigh instability on an initial liquid bridge and that connects two consecutively forming droplets. Based on the analysis of V. Entov and J. Hinch [1], the stability and thinning dynamics of this liquid bridge has been described theoretically in great detail, and the predicted dynamics have been confirmed experimentally in several publications. In particular, a recent publication by C. Wagner et al. [2] describes an analytical solution for this elastocapillary (EC) balance regime, that allows a quantitative description of the breakup time for a known relaxation time and finite extensibility of the polymer in solutions, once the onset point of this EC regime I known. However, their analysis for the description of this onset point was based on the assumption of a viscid fluid. Since many dilute polymer in practical applications involve solvents that behave inviscid during filament thinning, we present in this paper an analytical solution for the evolution of the polymer stretch in an inviscid solvent, based on the FENE-P model, that allows us to quantitatively predict the breakup time of inviscid-elastic filaments. Predictions of this model are compared to experimental results for a number of model polymer solutions that span the relevant range of intrinsic Deborah and Elastocapillary numbers for actual applications.

[1] V.M. Entov, E.J. Hinch, JNNFM 72 (1997), 31-53. [2] C. Wagner, L. Bourouiba, G.H. McKinley, JNNFM 218 (2015), 53-61.