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Interface determination in bicomponent extrusion
Author(s) -
Karagiannis A.,
Mavridis H.,
Hrymak A. N.,
Vlachopoulos J.
Publication year - 1988
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760281507
Subject(s) - materials science , breakup , dissipation , mechanics , extrusion , viscosity , viscous liquid , finite element method , flow (mathematics) , interface (matter) , thermodynamics , composite material , physics , capillary number , capillary action
The unidirectional flow of two immiscible fluids with different viscosities in a long die of arbitrary shape is considered. Mathematically, the problem has a continuum of solutions corresponding to arbitrarily prescribed interface shapes, but experimental evidence indicates the existence of a unique interface shape with the less viscous fluid encapsulating the more viscous fluid. With the introduction of the minimum viscous dissipation principle, which postulates that the amount of viscous dissipation is minimized for a given flow rate, the problem becomes a nonlinearly constrained optimization problem. A generalized reduced gradient/finite element method combination is used to predict the interface shape when two inelastic fluids are considered. The effect of the viscosity ratio and flow‐rate ratio on the interface shape is examined for different die geometries. Inner layer breakup phenomena are predicted and explained for complex die geometries.