Premium
Transient response of two‐layer slot coating flows to periodic disturbances
Author(s) -
Maza Danmer,
Carvalho Marcio S.
Publication year - 2015
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.14734
Subject(s) - coating , perturbation (astronomy) , transient (computer programming) , mechanics , oscillation (cell signaling) , layer (electronics) , materials science , steady state (chemistry) , amplitude , flow (mathematics) , transient response , control theory (sociology) , composite material , physics , computer science , optics , chemistry , engineering , electrical engineering , biochemistry , control (management) , quantum mechanics , artificial intelligence , operating system
Coating uniformity requirement is becoming more severe as new products come into the market. Coating processes have to be designed not only based on the steady‐state operation but also taking into account how the flow responds to ongoing disturbances on process conditions. These disturbances may lead to thickness variation on the deposited liquid layers that may be unacceptable for product performance. This study extends available transient analysis of single‐layer slot coating to determine the amplitude of the oscillation of each individual coated layer in two‐layer slot coating process in response to small periodic perturbation on different operating parameters. The predictions were obtained by solving the complete transient Navier–Stokes equations for free surface flows. The results show the most dangerous perturbations and how the deposited film thickness variations of each layer can be minimized by changing the geometry of the die lip and liquid viscosities. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1699–1707, 2015