Investigations of slip in capillary flow by laser-Doppler velocimetry and their relations to melt fracture
Münstedt H (2015)
Publication Type: Conference contribution
Publication year: 2015
Journal
Publisher: American Institute of Physics Inc.
Book Volume: 1662
Conference Proceedings Title: AIP Conference Proceedings
Event location: Zlin
ISBN: 9780735413061
DOI: 10.1063/1.4918876
Abstract
Flow profiles within a slit capillary are measured by laser-Doppler velocimetry. They allow the direct determination of the slip velocity at the wall. It is demonstrated that the flow profile of the melt of a high density polyethylene (HDPE) already shows slip components at small shear rates. At high shear rates the slip is dominant and a plug flow is found. Furthermore, it is shown that the surface irregularity called "shark skin" is generated at the slit exit by the stretching of surface layers at pronounced elongational rates. These elongational rates are due to the differences between the flow velocities at the wall of the slit and those of the extruded strand. It is shown how "shark skin" may be avoided when the elongational rate is reduced by introducing slip of the melt in the slit using special additives.
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How to cite
APA:
Münstedt, H. (2015). Investigations of slip in capillary flow by laser-Doppler velocimetry and their relations to melt fracture. In Martin Zatloukal (Eds.), AIP Conference Proceedings. Zlin, CZ: American Institute of Physics Inc..
MLA:
Münstedt, Helmut. "Investigations of slip in capillary flow by laser-Doppler velocimetry and their relations to melt fracture." Proceedings of the 6th International Conference on Novel Trends in Rheology, Zlin Ed. Martin Zatloukal, American Institute of Physics Inc., 2015.
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