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Converging flow analysis, entrance pressure drops, and vortex sizes: Measurements and calculated values
Author(s) -
Carrot Christian,
Guillet Jacques,
Fulchiron René
Publication year - 2001
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.10905
Subject(s) - materials science , mechanics , vortex , constitutive equation , rotational symmetry , flow (mathematics) , particle (ecology) , capillary action , thermodynamics , physics , composite material , geology , oceanography , finite element method
The use of converging flows for the determination of the elongational behavior of polymer melts is interesting provided that the solving of the inverse problem is fast. For this purpose, this paper shows that the entrance pressure drops that occur during the axisymmetric flow of a polymer melt from the reservoir of a capillary rheometer into a cylindrical die with flat entry can be rapidly calcylated using a Wagner constitutive equation and Protean coordinates. This calculation technique performs particle tracking, which is absolutely necessary when using integral constitutive equations. In turn, the method also enables the determination of the particle path in the entrance zone and gives the boundary of the vertex. The appropriate solution is obtained through the minimization of the power consumption in the entrance zone. Calculation results are compared with experimental pressure drops and vortex pictures using two well‐characterized polyethylenes and show good agreement.