Thixotropic flow of toothpaste through extrusion dies

Ardakani, HA; Mitsoulis, E; Hatzikiriakos, SG

dc.contributor.author	Ardakani, HA	en
dc.contributor.author	Mitsoulis, E	en
dc.contributor.author	Hatzikiriakos, SG	en
dc.date.accessioned	2014-03-01T01:37:28Z
dc.date.available	2014-03-01T01:37:28Z
dc.date.issued	2011	en
dc.identifier.issn	0377-0257	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/21509
dc.subject	Axisymmetric contraction	en
dc.subject	Paste extrusion	en
dc.subject	Slip law	en
dc.subject	Structural parameter	en
dc.subject	Thixotropy	en
dc.subject	Toothpaste	en
dc.subject.classification	Mechanics	en
dc.subject.other	Axisymmetric contraction	en
dc.subject.other	Slip law	en
dc.subject.other	Structural parameter	en
dc.subject.other	Thixotropy	en
dc.subject.other	Toothpaste	en
dc.subject.other	Colloids	en
dc.subject.other	Integral equations	en
dc.subject.other	Rheology	en
dc.subject.other	Rheometers	en
dc.subject.other	Yield stress	en
dc.subject.other	Extrusion	en
dc.title	Thixotropic flow of toothpaste through extrusion dies	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.jnnfm.2011.08.004	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.jnnfm.2011.08.004	en
heal.language	English	en
heal.publicationDate	2011	en
heal.abstract	A commercial toothpaste is investigated in this work as a model paste system to study its processing characteristics in capillary flow using various dies. Its rheological behaviour has been determined as that of a yield-stress, thixotropic material with a time-dependent behaviour, and severe slip at the wall. The rheological data obtained from a parallel-plate rheometer were used to formulate a constitutive equation with a structural parameter which obeys a kinetic equation, typically used to model thixotropy. The predictive capabilities of this model are tested against capillary data for a variety of capillary dies having different length-to-diameter ratios (L/D), contraction angles (2 alpha), and contraction ratios (D-b/D)(2), where D-b is the diameter of the barrel of the capillary rheometer. The major trends are well captured by the thixotropic model and show that slip is the essential parameter in predicting the flow behaviour of toothpaste. (C) 2011 Elsevier B.V. All rights reserved.	en
heal.publisher	ELSEVIER SCIENCE BV	en
heal.journalName	Journal of Non-Newtonian Fluid Mechanics	en
dc.identifier.doi	10.1016/j.jnnfm.2011.08.004	en
dc.identifier.isi	ISI:000296547200006	en
dc.identifier.volume	166	en
dc.identifier.issue	21-22	en
dc.identifier.spage	1262	en
dc.identifier.epage	1271	en