Numerical simulation of entry flow of the IUPAC-LDPE melt

Mitsoulis, E

dc.contributor.author	Mitsoulis, E	en
dc.date.accessioned	2014-03-01T01:16:49Z
dc.date.available	2014-03-01T01:16:49Z
dc.date.issued	2001	en
dc.identifier.issn	0377-0257	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/14241
dc.subject	entry flow	en
dc.subject	polymer melts	en
dc.subject	uniaxial elongational viscosity	en
dc.subject	planar extensional viscosity	en
dc.subject	vortex growth	en
dc.subject	viscoelasticity	en
dc.subject	integral constitutive equations	en
dc.subject.classification	Mechanics	en
dc.subject.other	Computer simulation	en
dc.subject.other	Creep	en
dc.subject.other	Integral equations	en
dc.subject.other	Kinematics	en
dc.subject.other	Low density polyethylenes	en
dc.subject.other	Mathematical models	en
dc.subject.other	Relaxation processes	en
dc.subject.other	Shear stress	en
dc.subject.other	Strain rate	en
dc.subject.other	Stress analysis	en
dc.subject.other	Viscous flow	en
dc.subject.other	Vortex flow	en
dc.subject.other	Entry flow	en
dc.subject.other	Papanastasiou-Scriven-Macosko models	en
dc.subject.other	Planar extensional viscosity	en
dc.subject.other	Polymer melts	en
dc.subject.other	Uniaxial elongational viscosity	en
dc.subject.other	Non Newtonian flow	en
dc.subject.other	fluid flow	en
dc.subject.other	melting	en
dc.subject.other	polymer	en
dc.subject.other	shear flow	en
dc.subject.other	viscosity	en
dc.title	Numerical simulation of entry flow of the IUPAC-LDPE melt	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/S0377-0257(00)00183-X	en
heal.identifier.secondary	http://dx.doi.org/10.1016/S0377-0257(00)00183-X	en
heal.language	English	en
heal.publicationDate	2001	en
heal.abstract	Numerical simulations have been undertaken for the creeping entry flow of a well-characterized polymer melt (IUPAC-LDPE) in a 4:1 axisymmetric and a 14:1 planar contraction. The fluid has been modeled using an integral constitutive equation of the K-BKZ type with a spectrum of relaxation times (Papanastasiou-Scriven-Macosko or PSM model). Numerical values for the constants appearing in the equation have been obtained from fitting shear viscosity and normal stress data as measured in shear and elongational data from uniaxial elongation experiments. The numerical solutions show that in the axisymmetric contraction the vortex in the reservoir first increases with increasing flow rate (or apparent shear rate), goes through a maximum and then decreases following the behavior of the uniaxial elongational viscosity. For the planar contraction, the vortex diminishes monotonically with increasing flow rate following the planar extensional viscosity. This kinematic behavior is not in agreement with recent experiments. The PSM strain-memory function of the model is then modified to account for strain-hardening in planar extension. Then the vortex pattern shows an increase in both axisymmetric and planar flows. The results for planar flow are compared with recent experiments showing the correct trend. (C) 2001 Elsevier Science B.V. All rights reserved.	en
heal.publisher	Elsevier Science Publishers B.V., Amsterdam, Netherlands	en
heal.journalName	Journal of Non-Newtonian Fluid Mechanics	en
dc.identifier.doi	10.1016/S0377-0257(00)00183-X	en
dc.identifier.isi	ISI:000166757100002	en
dc.identifier.volume	97	en
dc.identifier.issue	1	en
dc.identifier.spage	13	en
dc.identifier.epage	30	en