Papers by Wieslaw Suszynski
Journal of Coatings Technology and Research, Aug 11, 2021
Previous studies reported that single-phase liquid curtains become more stable with increasing Oh... more Previous studies reported that single-phase liquid curtains become more stable with increasing Ohnesorge number. Many liquid films used in the coating industry are types of emulsion samples. Despite this fact, the effect of multiphase liquids on the dynamics of the curtain breakup has not yet been considered. This study explores the stability of emulsion curtain coating via high-speed visualization. The critical condition at the onset of curtain breakup was determined by finding the flow rate below which the curtain broke. Curtain breakup was observed via a hole initiation within the curtain. The results reveal that curtain breakup dynamics is governed by the characteristic dynamic viscosity and the surface tension. The emulsion curtain stability, defined by Weber number, increases as Ohnesorge number rises, similar to the single-phase liquid (i.e., Newtonian and pure shear thinning) curtain stability. The critical web speed at which the contact line moves upstream of the curtain, a phenomenon called heel formation, and that at which air entrainment occurs, were determined for emulsion solutions at different flow rates. The results reveal that the surface tension increase delays the onset of air entrainment which could help to conduct faster curtain coating substrates with emulsion liquid films.
Bookmarks Related papers MentionsView impact
Industrial & Engineering Chemistry Research, Jun 29, 2012
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
International Journal of Pharmaceutics, May 1, 2021
Softgel encapsulation is an important manufacturing process used to produce convenient oral dosag... more Softgel encapsulation is an important manufacturing process used to produce convenient oral dosage forms of pharmaceuticals and dietary supplements. An important step in this process involves the injection of a fill material into a gelatin lined mold, and poor flow of the fill material during the injection may lead to undesired defects. We investigated the effect of fill composition on the injection behavior of an oil-based tricalcium phosphate (TCP) suspension containing lecithin by rheological measurements, capillary breakup extensional rheometry (CaBER), and high-speed flow visualization experiments. Shear rheology for TCP suspensions in soybean oil at concentrations of 27.8 wt.% and 55.6 wt.% showed shear thinning behaviors both with and without the addition of lecithin. Adding up to 0.5 wt.% lecithin led to decreases in shear viscosity, while additions up to 1 wt.% caused a slight increase. Results from CaBER and breakoff studies indicated that the length at which flow breakoff occurs was closely related to the Ohnesorge number, a dimensionless parameter representing the relative importance of viscous to surface-tension forces during breakoff, with higher values correlated to longer breakoff lengths. An optimal lecithin concentration exists for minimized TCP suspension viscosity which shortens flow breakoff times and improves softgel capsule seaming quality.
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Journal of Coatings Technology and Research, May 29, 2015
Bookmarks Related papers MentionsView impact
Journal of Non-newtonian Fluid Mechanics, 2019
Bookmarks Related papers MentionsView impact
Industrial & Engineering Chemistry Research, Nov 9, 2018
Bookmarks Related papers MentionsView impact
Journal of Fluid Mechanics, Mar 31, 2020
Dynamic wetting failure in shear-thinning and shear-thickening liquids is examined in this paper.... more Dynamic wetting failure in shear-thinning and shear-thickening liquids is examined in this paper. Flow visualization experiments using a curtain-coating geometry suggest that shear thinning postpones the onset of wetting failure and the resulting air entrainment. To advance the fundamental understanding of the underlying physical mechanisms, a hydrodynamic model consisting of liquid displacing air in a rectangular channel in the absence of inertia is developed. Both shear thinning and shear thickening are considered by using Carreau-type models to describe the liquid rheology. Steady-state solutions are calculated using the Galerkin finite-element method and the critical capillary number where wetting failure occurs is identified. Shear thinning is found to postpone the onset of wetting failure whereas shear thickening is found to promote it. The underlying mechanism involves thickening/thinning of the air film as a consequence of shear thinning/thickening of the liquid and the tangential stress balance. The results can be interpreted in terms of an effective viscosity, and demonstrate that similar physical mechanisms govern dynamic wetting failure in Newtonian, shear-thinning and shear-thickening liquids.
Bookmarks Related papers MentionsView impact
Journal of Coatings Technology and Research, Aug 1, 2013
Bookmarks Related papers MentionsView impact
Journal of Chemical & Engineering Data, Apr 13, 2017
Bookmarks Related papers MentionsView impact
Fluids, Sep 30, 2022
Bookmarks Related papers MentionsView impact
Advanced Materials, Oct 19, 2015
Bookmarks Related papers MentionsView impact
Journal of Coatings Technology and Research, Sep 12, 2019
Bookmarks Related papers MentionsView impact
Journal of Microscopy, 2008
Bookmarks Related papers MentionsView impact
Journal of Non-newtonian Fluid Mechanics, Jul 1, 2018
Bookmarks Related papers MentionsView impact
Green Chemistry, 2009
Bookmarks Related papers MentionsView impact
Bulletin of the American Physical Society, Nov 21, 2016
Bookmarks Related papers MentionsView impact
Journal of Coatings Technology and Research, Sep 26, 2012
Bookmarks Related papers MentionsView impact
Journal of Fluid Mechanics, Jan 28, 2021
Bookmarks Related papers MentionsView impact
Uploads
Papers by Wieslaw Suszynski