Annular Extrudate Swell of Newtonian Fluids revisited: Extended range of compressible simulations

Mitsoulis, E

dc.contributor.author	Mitsoulis, E	en
dc.date.accessioned	2014-03-01T01:29:51Z
dc.date.available	2014-03-01T01:29:51Z
dc.date.issued	2009	en
dc.identifier.issn	0098-2202	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/19379
dc.subject	Annular flow	en
dc.subject	Blow molding	en
dc.subject	Compressibility	en
dc.subject	Exit correction	en
dc.subject	Extrudate swell	en
dc.subject	Foam extrusion	en
dc.subject	Linear law	en
dc.subject	Newtonian fluid	en
dc.subject.classification	Engineering, Mechanical	en
dc.subject.other	Annular flow	en
dc.subject.other	Annular flows	en
dc.subject.other	Extrudate swell	en
dc.subject.other	Foam extrusion	en
dc.subject.other	Linear law	en
dc.subject.other	Newtonian fluids	en
dc.subject.other	Blow molding	en
dc.subject.other	Computer simulation	en
dc.subject.other	Extrusion molding	en
dc.subject.other	Finite element method	en
dc.subject.other	Fluids	en
dc.subject.other	Plastics molding machines	en
dc.subject.other	Compressibility	en
dc.title	Annular Extrudate Swell of Newtonian Fluids revisited: Extended range of compressible simulations	en
heal.type	journalArticle	en
heal.identifier.primary	10.1115/1.3155996	en
heal.identifier.secondary	http://dx.doi.org/10.1115/1.3155996	en
heal.identifier.secondary	071203	en
heal.language	English	en
heal.publicationDate	2009	en
heal.abstract	In a recent article (Mitsoulis, 2007, ""Annular Extrudate Swell of Newtonian Fluids: Effects of Compressibility and Slip at the Wall,"" ASME J. Fluids Eng., 129, pp. 1384- 1393), numerical simulations were undertaken for the benchmark problem of annular extrudate swell of Newtonian fluids. The effects of weak compressibility and slip at the wall were studied through simple linear laws. While slip was studied in the full range of parameter values, compressibility was confined within a narrow range of values for weakly compressible fluids, where the results were slightly affected. This range is now markedly extended (threefold), based on a consistent finite element method formulation for the continuity equation. Such results correspond to foam extrusion, where compressibility can be substantial. The new extended numerical results are given for different inner/outer diameter ratios k under steady-state conditions for Newtonian fluids. They provide the shape of the extrudate, and, in particular, the thickness and diameter swells, as a function of the dimensionless compressibility coefficient B. The pressures from the simulations have been used to compute the excess pressure losses in the flow field (exit correction). As before, weak compressibility slightly affects the thickness swell (about 1% in the range of 0≤B≤0.02) mainly by a swell reduction, after which a substantial and monotonic increase occurs for B7 lt;0.02. The exit correction increases with increasing compressibility levels in the lower B-range and is highest for the tube (k=0) and lowest for the slit (k=1). Then it passes through a maximum around B≈0.02, after which it decreases slowly. This decrease is attributed to the limited length of the flow channel (here chosen to be eight die gaps). Copyright © 2009 by ASME.	en
heal.publisher	ASME-AMER SOC MECHANICAL ENG	en
heal.journalName	Journal of Fluids Engineering, Transactions of the ASME	en
dc.identifier.doi	10.1115/1.3155996	en
dc.identifier.isi	ISI:000267369900006	en
dc.identifier.volume	131	en
dc.identifier.issue	7	en
dc.identifier.spage	0712031	en
dc.identifier.epage	07120310	en