?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Fmiis.maths.ox.ac.uk%2Fmiis%2F385%2F&rft.title=Thermal+Modeling+in+Polymer+Extrusion&rft.creator=Berg%2C+J.B.&rft.creator=Bokhove%2C+O.&rft.creator=Peletier%2C+M.&rft.creator=Williams%2C+J.F.&rft.creator=Zwart%2C+H.&rft.subject=Materials&rft.description=In+this+paper+we+consider+thermal+effects+of+polymer+flows+through+a+cylindrical+die.+First%2C+we+derive+a+model+for+the+oscillatory+behavior+of+polymer+flow+in+an+extruder+given+a+functional+relation+between+the+pressure+and+flow+rate.+A+simple+isothermal+but+temperature+dependent+model+is+constructed+to+find+this+relation.+Unfortunately%2C+the+model+is+shown+to+be+invalid+in+the+physical+regime+of+interest.+We+present+several+arguments+to+suggest+that+the+isothermal+assumption+is+reasonable+but+that+a+more+detailed+understanding+of+the+small-scale+molecular+dynamics+near+the+boundary+may+be+required.+Second%2C+we+show+that+a+simplified+model+for+thermoflow+multiplicity+in+a+cooled+tube+is+inconsistent%2C+when+the+stationary+non-Newtonian+flow+is+assumed+to+be+incompressible+without+radial+pressure+gradients+and+without+radial+velocity.+This+inconsistency+can+be+removed+by+allowing+for+weak+compressibility+effects+in+the+down-steam+area.&rft.date=2000&rft.type=Study+Group+Report&rft.type=NonPeerReviewed&rft.format=application%2Fpdf&rft.language=en&rft.identifier=http%3A%2F%2Fmiis.maths.ox.ac.uk%2Fmiis%2F385%2F1%2FThermal-modeling-in-polymer-extrusion.pdf&rft.identifier=++Berg%2C+J.B.+and+Bokhove%2C+O.+and+Peletier%2C+M.+and+Williams%2C+J.F.+and+Zwart%2C+H.++(2000)+Thermal+Modeling+in+Polymer+Extrusion.++%5BStudy+Group+Report%5D+++++