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Air entrainment and dynamic contact angles in hydrodynamics of liquid coating
Author(s) -
Esmail M. N.,
Ghannam M. T.
Publication year - 1990
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450680203
Subject(s) - capillary action , entrainment (biomusicology) , viscosity , contact angle , materials science , capillary number , mechanics , air entrainment , coating , thermodynamics , composite material , physics , rhythm , acoustics
The dynamic contact angles and the phenomenon of entrainment of air bubbled in liquid coating processes are investigated by experimental measurements in which liquid viscosity was varied. The technique consists of using a continuously rotating liquid roller, which is submerged in a liquid pool. The test liquids are glycerol solutions with viscosities in the range 197 < μ < 748 mPa.s. The capillary length (σ/ρg) ½ is used as a characteristic dimension. The dynamic contact angle is shown as a function of the capillary number and physical properties number. Dimensional correlations for air entrainment criteria are reported for moderate capillary numbers Ca < 2.