Numerical simulation of calendering viscoplastic fluids

Mitsoulis, E

dc.contributor.author	Mitsoulis, E	en
dc.date.accessioned	2014-03-01T01:28:53Z
dc.date.available	2014-03-01T01:28:53Z
dc.date.issued	2008	en
dc.identifier.issn	0377-0257	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/19018
dc.subject	Bingham plastics	en
dc.subject	Calendering	en
dc.subject	Papanastasiou model	en
dc.subject	Sheet thickness	en
dc.subject	Viscoplasticity	en
dc.subject	Yield stress	en
dc.subject	Yielded/unyielded regions	en
dc.subject.classification	Mechanics	en
dc.subject.other	Calendering	en
dc.subject.other	Calenders	en
dc.subject.other	Computer simulation	en
dc.subject.other	Crystallography	en
dc.subject.other	Materials science	en
dc.subject.other	Molecular beam epitaxy	en
dc.subject.other	Plasticity	en
dc.subject.other	Technology	en
dc.subject.other	Two dimensional	en
dc.subject.other	Viscoplasticity	en
dc.subject.other	Viscosity	en
dc.subject.other	Vortex flow	en
dc.subject.other	Yield stress	en
dc.subject.other	A posteriori	en
dc.subject.other	Bingham numbers	en
dc.subject.other	Bingham plastics	en
dc.subject.other	Deformation rates	en
dc.subject.other	Dimensionless form	en
dc.subject.other	Finite element method FEM	en
dc.subject.other	Finite thickness	en
dc.subject.other	Free surfaces	en
dc.subject.other	Herschel-Bulkley	en
dc.subject.other	Lubrication approximations	en
dc.subject.other	Newtonian	en
dc.subject.other	Newtonian viscous fluids	en
dc.subject.other	Numerica l results	en
dc.subject.other	Numerical simulations	en
dc.subject.other	Papanastasiou model	en
dc.subject.other	Shear-thinning	en
dc.subject.other	Sheet thickness	en
dc.subject.other	Steady-state conditions	en
dc.subject.other	Visco-plastic	en
dc.subject.other	Viscoplastic fluids	en
dc.subject.other	Vortex size	en
dc.subject.other	Yielded/unyielded regions	en
dc.subject.other	Finite element method	en
dc.subject.other	Calendering	en
dc.subject.other	Crystallography	en
dc.subject.other	Finite Element Analysis	en
dc.subject.other	Flow	en
dc.subject.other	Fluid Dynamics	en
dc.subject.other	Plasticity	en
dc.subject.other	Plastics	en
dc.subject.other	Simulation	en
dc.subject.other	Stresses	en
dc.subject.other	Viscosity	en
dc.title	Numerical simulation of calendering viscoplastic fluids	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.jnnfm.2008.03.001	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.jnnfm.2008.03.001	en
heal.language	English	en
heal.publicationDate	2008	en
heal.abstract	Numerical simulations have been undertaken for the process of calendering viscoplastic sheets with a finite thickness. The finite element method (FEM) is used to provide numerical results for a fixed entry thickness (known attachment point) under two-dimensional steady-state conditions. The Herschel-Bulkley-Papanastasiou model of viscoplasticity is used, which is valid for all ranges of deformation rates. Part of the solution is finding the shape of the free surfaces of the entering and exiting sheet. Yielded/unyielded regions are found a posteriori for a range of the dimensionless yield stress or Bingham number (Bn) from the Newtonian viscous fluid (Bn = 0) to a highly viscoplastic one (Bn = 1000). The 2D FEM results show limited unyielded regions between the rolls, in disagreement with the lubrication approximation theory (LAT). which predicts erroneous extended unyielded regions. However, LAT is good at predicting the excess sheet thickness over the thickness at the nip (hence the detachment point), the pressure distribution and all engineering quantities of interest in calendering. For thick entering sheets, viscoplasticity (and also shear-thinning) leads to excess sheet thickness as the dimensionless Bingham number increases; it reduces the vortex size in the fluid bank, and gives virtually no swelling at the exit from the rolls. All engineering quantities, given in a dimensionless form, increase substantially with the departure from the Newtonian values. (C) 2008 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.2008.03.001	en
dc.identifier.isi	ISI:000259658700001	en
dc.identifier.volume	154	en
dc.identifier.issue	2-3	en
dc.identifier.spage	77	en
dc.identifier.epage	88	en