Capillary flow of low-density polyethylene

Ansari, M; Zisis, T; Hatzikiriakos, SG; Mitsoulis, E

dc.contributor.author	Ansari, M	en
dc.contributor.author	Zisis, T	en
dc.contributor.author	Hatzikiriakos, SG	en
dc.contributor.author	Mitsoulis, E	en
dc.date.accessioned	2014-03-01T02:08:20Z
dc.date.available	2014-03-01T02:08:20Z
dc.date.issued	2012	en
dc.identifier.issn	00323888	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/29639
dc.subject.other	Bagley correction	en
dc.subject.other	Capillary dies	en
dc.subject.other	Effect of pressure	en
dc.subject.other	Excess pressure	en
dc.subject.other	Experimental data	en
dc.subject.other	L/D ratio	en
dc.subject.other	Nonisothermal	en
dc.subject.other	Pressure dependence	en
dc.subject.other	Relaxation modulus	en
dc.subject.other	Rheological characterization	en
dc.subject.other	Shear rates	en
dc.subject.other	Slip effects	en
dc.subject.other	Viscous models	en
dc.subject.other	Capillarity	en
dc.subject.other	Capillary flow	en
dc.subject.other	Polyethylenes	en
dc.subject.other	Thermoplastics	en
dc.subject.other	Pressure effects	en
dc.title	Capillary flow of low-density polyethylene	en
heal.type	journalArticle	en
heal.identifier.primary	10.1002/pen.22130	en
heal.identifier.secondary	http://dx.doi.org/10.1002/pen.22130	en
heal.publicationDate	2012	en
heal.abstract	The capillary flow of a commercial low-density polyethylene (LDPE) melt was studied both experimentally and numerically. The excess pressure drop due to entry (Bagley correction), the compressibility, the effect of pressure on viscosity, and the possible slip effects on the capillary data analysis have been examined. Using a series of capillary dies having different diameters, D, and length-to-diameter L/D ratios, a full rheological characterization has been carried out, and the experimental data have been fitted both with a viscous model (Carreau-Yasuda) and a viscoelastic one (the Kaye-Bernstein, Kearsley, Zapas/Papanastasiou, Scriven, Macosko, or K-BKZ/PSM model). Particular emphasis has been given on the pressure-dependence of viscosity, with a pressure-dependent coefficient βp. For the viscous model, the viscosity is a function of both temperature and pressure. For the viscoelastic K-BKZ model, the time erature shifting concept has been used for the non-isothermal calculations, while the time-pressure shifting concept has been used to shift the relaxation moduli for the pressure-dependence effect. It was found that only the viscoelastic simulations were capable of reproducing the experimental data well, while any viscous modeling always underestimates the pressures, especially at the higher apparent shear rates and L/D ratios. © 2012 Society of Plastics Engineers.	en
heal.journalName	Polymer Engineering and Science	en
dc.identifier.doi	10.1002/pen.22130	en
dc.identifier.volume	52	en
dc.identifier.issue	3	en
dc.identifier.spage	649	en
dc.identifier.epage	662	en