Fountain flow of pseudoplastic and viscoplastic fluids

Mitsoulis, E

dc.contributor.author	Mitsoulis, E	en
dc.date.accessioned	2014-03-01T01:33:30Z
dc.date.available	2014-03-01T01:33:30Z
dc.date.issued	2010	en
dc.identifier.issn	0377-0257	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/20454
dc.subject	Bingham-Papanastasiou model	en
dc.subject	Fountain flow	en
dc.subject	Front pressure (exit) correction	en
dc.subject	Herschel-Bulkley model	en
dc.subject	Injection molding	en
dc.subject	Power-law fluids	en
dc.subject	Pseudoplasticity	en
dc.subject	Viscoplasticity	en
dc.subject	Yield stress	en
dc.subject.classification	Mechanics	en
dc.subject.other	Fountain flow	en
dc.subject.other	Herschel-Bulkley model	en
dc.subject.other	Papanastasiou model	en
dc.subject.other	Power law fluid	en
dc.subject.other	Pseudoplasticity	en
dc.subject.other	Fountains	en
dc.subject.other	Injection molding	en
dc.subject.other	Non Newtonian flow	en
dc.subject.other	Plastic molds	en
dc.subject.other	Plasticity	en
dc.subject.other	Simulators	en
dc.subject.other	Viscoplasticity	en
dc.subject.other	Viscosity	en
dc.subject.other	Yield stress	en
dc.title	Fountain flow of pseudoplastic and viscoplastic fluids	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.jnnfm.2009.09.001	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.jnnfm.2009.09.001	en
heal.language	English	en
heal.publicationDate	2010	en
heal.abstract	Numerical simulations have been undertaken for the benchmark problem of fountain flow present in injection-mold filling. The Finite Element Method (FEM) is used to provide numerical results for both cases of planar and axisymmetric domains under steady-state conditions. The Herschel-Bulkley model of viscoplasticity is used, which reduces with appropriate modifications to the Bingham, power-law and Newtonian models. The present results extend previous ones regarding the shape of the front, which is essential in correctly capturing the flow field. In particular the centreline front position is found as a function of the dimensionless power-law index (in the case of pseudoplasticity) and the dimensionless yield stress (in the case of viscoplasticity). The pressures from the simulations have been used to compute the excess pressure losses in the system (front pressure correction or exit correction). Both shear-thinning and shear-thickening lead to more extended front positions relative to the Newtonian values. which are 0.895 for the planar case and 0.835 for the axisymmetric one. Viscoplasticity leads also to more extended front positions as the dimensionless yield stress goes from zero (Newtonian behaviour) to higher values of the yield stress. In both cases of non-Newtonian behaviour, the front tends to follow the development of the fully developed Poiseuille velocity profile, which tends towards a plug-like profile at the extreme cases of non-Newtonianness. The front pressure (exit) correction increases monotonically with the decrease in the power-law index and the increase in the dimensionless yield stress. (C) 2009 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.2009.09.001	en
dc.identifier.isi	ISI:000274272800005	en
dc.identifier.volume	165	en
dc.identifier.issue	1-2	en
dc.identifier.spage	45	en
dc.identifier.epage	55	en