Flow limits in slide coating
2009-12
Loading...
View/Download File
Persistent link to this item
Statistics
View StatisticsJournal Title
Journal ISSN
Volume Title
Title
Flow limits in slide coating
Authors
Published Date
2009-12
Publisher
Type
Thesis or Dissertation
Abstract
Slide coating is the leading method for simultaneous multilayer coating. The thickness of the coated layer is set solely by the flow rate and speed, and independent from other process conditions. The uniformity of the layer, however, can strongly depend on the other process conditions and uniform coating can only be achieved in certain ranges of operating conditions. The parameter space in operating conditions where coating is feasible is referred as coating window. Slide coating window, even for single-layer case, is not well understood as the slot coating window, another popular premetered coating method. The goals of this thesis are to uncover the mechanisms of coating bead breakdown at the edges of the windows and to predict critical operating conditions corresponding to the bead breakup. The study was initiated by developing a one-dimensional viscocapillary model of slide coating. The viscocapillary model are found to be accurate only at low capillary numbers and small gap-to-thickness ratio. The accuracy of the viscocapillary model is then improved by augmenting it with full 2-D Navier-Stokes theory at the coating bead region, where the flow is fully two-dimensional. The hybrid model is as accurate as the full 2-D model, providing that the matching conditions are assigned properly and their locations are far enough such that the approximations employed in deriving the viscocapillary model remain valid there. These tools are employed with the addition of flow visualization experiments for uncovering bead breakup mechanisms at low vacuum, high vacuum, and low flow limits. In addition to uncovering bead breakup mechanisms, theoretical modeling also yields to predictions of the critical operating conditions that mark the edges of coating windows. The predicted coating window agrees qualitatively with the flow visualization experiments.
Description
University of Minnesota Ph.D. dissertation. December 2009. Major: Chemical Engineering. Advisor: Marcio S. Carvalho. 1 computer file (PDF); xi, 121 pages.
Related to
Replaces
License
Collections
Series/Report Number
Funding information
Isbn identifier
Doi identifier
Previously Published Citation
Other identifiers
Suggested citation
Tjiptowidjojo, Kristianto. (2009). Flow limits in slide coating. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/59025.
Content distributed via the University Digital Conservancy may be subject to additional license and use restrictions applied by the depositor. By using these files, users agree to the Terms of Use. Materials in the UDC may contain content that is disturbing and/or harmful. For more information, please see our statement on harmful content in digital repositories.