A study of various factors affecting Newtonian extrudate swell

Mitsoulis, E; Georgiou, GC; Kountouriotis, Z

dc.contributor.author	Mitsoulis, E	en
dc.contributor.author	Georgiou, GC	en
dc.contributor.author	Kountouriotis, Z	en
dc.date.accessioned	2014-03-01T02:07:33Z
dc.date.available	2014-03-01T02:07:33Z
dc.date.issued	2012	en
dc.identifier.issn	00457930	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/29570
dc.subject	Compressibility	en
dc.subject	Exit correction	en
dc.subject	Extrudate swell	en
dc.subject	Extrusion	en
dc.subject	Gravity	en
dc.subject	Inertia	en
dc.subject	Newtonian fluid	en
dc.subject	Pressure-dependence of viscosity	en
dc.subject	Surface tension	en
dc.subject	Wall slip	en
dc.subject.other	Extrudate swell	en
dc.subject.other	Inertia	en
dc.subject.other	Newtonian fluids	en
dc.subject.other	Pressure dependence	en
dc.subject.other	Wall slip	en
dc.subject.other	Compressibility	en
dc.subject.other	Extrusion	en
dc.subject.other	Gravitation	en
dc.subject.other	Reynolds number	en
dc.subject.other	Swelling	en
dc.subject.other	Surface tension	en
dc.title	A study of various factors affecting Newtonian extrudate swell	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.compfluid.2011.12.019	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.compfluid.2011.12.019	en
heal.publicationDate	2012	en
heal.abstract	Finite-element simulations have been undertaken for the benchmark problem of extrudate swell present in extrusion. Both cases of planar and axisymmetric domains were considered under laminar, isothermal, steady-state conditions for Newtonian fluids. The effects of inertia, gravity, compressibility, pressure-dependence of the viscosity, slip at the wall, and surface tension are all considered individually in parametric studies covering a wide range of the relevant parameters. The present results extend previous ones regarding the shape of the extrudate and in particular the swelling ratio. In addition, the excess pressure losses in the system (exit correction) were computed. The effect of the domain length is also studied and is found to be of importance in all cases, except for slip and surface tension effects. The effect of the extrudate length is particularly important for inertia and gravity flows. Inertia reduces the swelling down to the asymptotic theoretical values at infinite Reynolds numbers. Gravity acting in the direction of flow also reduces exponentially the swelling. When the flow is creeping and gravity is zero, surface tension, slip at the wall, and pressure-dependence of viscosity, all decrease the swelling monotonically, while compressibility increases it after a small initial reduction. The exit correction decreases monotonically with inertia, gravity, and slip, increases monotonically with compressibility and pressure-dependence of the viscosity, and is not affected by surface tension. © 2011 Elsevier Ltd.	en
heal.journalName	Computers and Fluids	en
dc.identifier.doi	10.1016/j.compfluid.2011.12.019	en
dc.identifier.volume	57	en
dc.identifier.spage	195	en
dc.identifier.epage	207	en