eprintid: 385 rev_number: 10 eprint_status: archive userid: 7 dir: disk0/00/00/03/85 datestamp: 2011-11-26 20:29:43 lastmod: 2015-05-29 20:00:32 status_changed: 2011-11-26 20:29:43 type: report metadata_visibility: show item_issues_count: 0 creators_name: Berg, J.B. creators_name: Bokhove, O. creators_name: Peletier, M. creators_name: Williams, J.F. creators_name: Zwart, H. title: Thermal Modeling in Polymer Extrusion ispublished: pub subjects: materials studygroups: esgi39 full_text_status: public abstract: In this paper we consider thermal effects of polymer flows through a cylindrical die. First, 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, 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, we show that a simplified model for thermoflow multiplicity in a cooled tube is inconsistent, 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. date: 2000 citation: Berg, J.B. and Bokhove, O. and Peletier, M. and Williams, J.F. and Zwart, H. (2000) Thermal Modeling in Polymer Extrusion. [Study Group Report] document_url: http://miis.maths.ox.ac.uk/miis/385/1/Thermal-modeling-in-polymer-extrusion.pdf