Next Article in Journal
Influence of Two Polymer-Based Superplasticizers (Poly-naphthalene Sulfonate, PNS, and Lignosulfonate, LS) on Compressive and Flexural Strength, Freeze-Thaw, and Sulphate Attack Resistance of Lime-Metakaolin Grouts
Next Article in Special Issue
A Novel Technique for Fiber Formation: Mechanotropic Spinning—Principle and Realization
Previous Article in Journal
Rubber-Filler Interactions in Polyisoprene Filled with In Situ Generated Silica: A Solid State NMR Study
Previous Article in Special Issue
Use of Irradiated Polymers after Their Lifetime Period
Article

Vortical Fountain Flows in Plasticating Screws

1
Department of Plastics Engineering, University of Massachusetts Lowell, 220 Pawtucket St., Lowell, MA 01854, USA
2
Fachbereich Maschinenbau und Kunststofftechnik, Hochschule Darmstadt, Gebäude C10, Schöfferstraße 3, Darmstadt 64295, Germany
*
Author to whom correspondence should be addressed.
Polymers 2018, 10(8), 823; https://doi.org/10.3390/polym10080823
Received: 23 June 2018 / Revised: 13 July 2018 / Accepted: 18 July 2018 / Published: 26 July 2018
(This article belongs to the Special Issue Model-Based Polymer Processing)
Variances in polymers processed by single-screw extrusion are investigated. While vortical flows are well known in the fluids community and fountain flows are well known to be caused by the frozen layers in injection molding, our empirical evidence and process modeling suggests the presence of vortical fountain flows in the melt channels of plasticating screws adjacent to a slower-moving solids bed. The empirical evidence includes screw freezing experiments with cross-sections of processed high-impact polystyrene (HIPS) blended with varying colorants. Non-isothermal, non-Newtonian process simulations indicate that the underlying causality is increased flow conductance in the melt pool caused by higher temperatures and shear rates in the recirculating melt pool. The results indicate the development of persistent, coiled sheet morphologies in both general purpose and barrier screw designs. The behavior differs significantly from prior melting and plastication models with the net effect of broader residence time distributions. The process models guide potential strategies for the remediation of the processing variances as well as potential opportunities to achieve improved dispersion as well as complex micro and nanostructures in polymer processing. View Full-Text
Keywords: single-screw extrusion; fountain flow; residence time distribution; polymer process simulation and modeling single-screw extrusion; fountain flow; residence time distribution; polymer process simulation and modeling
Show Figures

Graphical abstract

MDPI and ACS Style

Kazmer, D.O.; Grosskopf, C.M.; Venoor, V. Vortical Fountain Flows in Plasticating Screws. Polymers 2018, 10, 823. https://doi.org/10.3390/polym10080823

AMA Style

Kazmer DO, Grosskopf CM, Venoor V. Vortical Fountain Flows in Plasticating Screws. Polymers. 2018; 10(8):823. https://doi.org/10.3390/polym10080823

Chicago/Turabian Style

Kazmer, David O., Clemens M. Grosskopf, and Varun Venoor. 2018. "Vortical Fountain Flows in Plasticating Screws" Polymers 10, no. 8: 823. https://doi.org/10.3390/polym10080823

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop