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Licensed Unlicensed Requires Authentication Published by De Gruyter November 16, 2021

Numerical Simulation of Fluid Flow and Mixing Dynamics inside Planetary Roller Extruders

  • J. Winck and S. Frerich


In this contribution, the fluid flow and mixing dynamics inside planetary roller extruders are simulated using the finite element method (FEM) and the mesh superposition technique (MST). Three-dimensional configurations with planetary spindles of varying number and geometry of planetary spindles were created to analyse the influence of the spindle configuration and the rotational speed on the process behavior. Therefore, pressure gradients, flow velocities and directions, shear rates, the mixing index and residence time distributions were evaluated. The distributive and dispersive mixing efficiencies varied depending on the planetary spindle configuration, and these configurations thus suit different processing tasks. In comparison to the standard planetary spindles, the TT3 spindles, with their incomplete toothing, and the knob spindles, with their double transversal helical toothing, showed intense axial and radial mixing. In general, the mixing performance of the planetary roller extruder is explained by a high rate of extensional flow and frequent changes in flow type. The reported numerical approach allows, for the first time, a comprehensive observation of the process behavior of planetary roller extruders.

Judith Winck, Institute of Thermo and Fluid Dynamics, Ruhr University Bochum, Universitaetsstraße 150, 44801 Bochum, Germany


The authors would like to thank Entex Rust & Mitschke GmbH for providing extruder components for measurement.


Ashokan, B. K.: “Developing Methods for Design and Analysis of Continuous Mixers through 3D Numerical Simulation of Flow and Mixing", PhD Dissertation, Graduate School – New Brunswick, New Brunswick, Canada (2008), DOI:10.7282/T3JM29Z910.7282/T3JM29Z9Search in Google Scholar

Baehr, H. D., Stephan, K.: Wärme- und Stoffübertragung, Springer Vieweg, Berlin (2013), DOI:10.1007/978-3-642-36558-410.1007/978-3-642-36558-4Search in Google Scholar

Birr, T., “Verarbeitung von langglasfaserverstärkten Thermoplasten für Spritzgussanwendungen auf dem Planetwalzenextruder", PhD Dissertation, Technische Universität Berlin, Berlin (2016)Search in Google Scholar

Brito Bazan, M. M., “Mixing Studies in a Co-Kneader", PhD Dissertation, University of Montreal, Montreal (2011)Search in Google Scholar

Gorczyca, P., “Analyse und Optimierung von Einschneckenextrudern mit schnelldrehenden Schnecken", PhD Dissertation, Universität Duisburg-Essen, Duisburg, Deutschland (2011)Search in Google Scholar

Greger, M., “Entwicklung einer verstellbaren Dispergierringtechnik für Planetwalzenextruder", PhD Dissertation, Technische Universität Berlin, Berlin (2012)Search in Google Scholar

Hétu, J.-F., Ilinca, F., “Immersed Boundary Finite Elements for 3D Flow Simulations in Twin-Screw Extruders", Comput. Fluids, 87, 2–11 (2013), DOI:10.1016/j.compfluid.2012.06.02510.1016/j.compfluid.2012.06.025Search in Google Scholar

Kewitz, M., Malzahn, T., “Planetwalzenextruder für Kunststoff- und Kautschukverarbeitung", Plastverarbeiter, 52 (10), 138–140 (2001)Search in Google Scholar

Kohlgrüber, K., Bierdel, M., “Chapter 6.8 Extruderbauarten – Vergleich", in Polymer-Aufbereitung und Kunststoff-Compoundierung: Grundlagen, Apparate, Maschinen, Anwendungstechnik, Kohlgrüber, K., Bierdel, M., Rust, H. (Eds.), Hanser Publishers, Munich, p. 504–528 (2019), DOI:10.3139/978344646079910.3139/9783446460799Search in Google Scholar

Lecheler, S.: Numerische Strömungsberechnung, Springer Vieweg, Wiesbaden (2017), DOI:10.1007/978-3-658-19192-410.1007/978-3-658-19192-4Search in Google Scholar

Limper, A., Seibel, S. and Fattmann, G., “Compounding Unit Planetary Roller Extruder", Macromol. Mater. Eng., 287 (11), 815–823 (2002a), DOI:10.1002/mame.20029001110.1002/mame.200290011Search in Google Scholar

Limper, A., Seibel, S., Wefelmeier, C.-J. and Roth, M., “Homogene Compounds: Kämmende Spindeln verbessern die Mischwirkung im Planetwalzenextruder", Kunststoffe, 92, 83–86 (2002b)Search in Google Scholar

Moldflow, Moldflow Material Testing Report NatureWorks PLA, Moldflow Plastics Labs, Ithaca, USA (2007)Search in Google Scholar

Othman, N., Ansari, M., Zisis, T., Mitsoulis, E. and Hatzikiriakos, S. G., “Entry Flows of Polylactides with Slip", J. Non-Newtonian Fluid Mech., 210, 78–84 (2014), DOI:10.1016/j.jnnfm.2014.06.00210.1016/j.jnnfm.2014.06.002Search in Google Scholar

Polyflow, Polyflow User’s Guide, ANSYS Inc., Canonsburg, USA (2016)Search in Google Scholar

Rudloff, J., Bastian, M., Heidemeyer, P. and Kretschmer, K., “Modellierung von Planetwalzenextrudern", Kunststoffe, 6, 55–58 (2011)Search in Google Scholar

Rust, H., Birr, T. and Lange, H., “Chapter 6.5 Planetwalzenextruder", in Polymer-Aufbereitung und Kunststoff-Compoundierung: Grundlagen, Apparate, Maschinen, Anwendungstechnik, Kohlgrüber, K., Bierdel, M., Rust, H. (Eds.), Hanser Publishers, Munich, p. 415–453 (2019)10.3139/9783446460799Search in Google Scholar

Sarhangi Fard, A., Hulsen, M. A., Meijer, H. E. H., Famili, N. M. H. and Anderson, P. D., “Adaptive Non-Conformal Mesh Refinement and Extended Finite Element Method for Viscous Flow inside Complex Moving Geometries", Int. J. Numer. Methods Fluids, 68, 1031–1052 (2012), DOI:10.1002/fld.259510.1002/fld.2595Search in Google Scholar

Stehr, R., “Verarbeitung technischer Kunststoffe; ein Beitrag zur sicherheitsgerechten und wirtschaftlichen Aufbereitung auf dem Planetwalzenextruder", PhD Dissertation, Bergische Universität Wuppertal, Wuppertal, Germany (1990)Search in Google Scholar

Stewering, J., “Dreidimensionale Simulation und Visualisierung von Strömungs- und Mischprozessen im Doppelschneckenextruder“, PhD Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany (2008)Search in Google Scholar

Tang, H., Wrobel, L. C. and Fan, Z., “Fluid Flow Aspects of Twin-Screw Extruder Process: Numerical Simulations of TSE Rheomixing", Modell. Simul. Mater. Sci. Eng., 11, 771–790 (2003), DOI:10.1088/0965-0393/11/5/30510.1088/0965-0393/11/5/305Search in Google Scholar

Tang, H., Zong, Y. and Zhao, L., “Numerical Simulation of Micromixing Effect on the Reactive Flow in a Co-Rotating Twin Screw Extruder", Chinese Journal of Chemical Engineering, 24, 1135–1146 (2016), DOI:10.1016/j.cjche.2016.04.04010.1016/j.cjche.2016.04.040Search in Google Scholar

Vyakaranam, K. V., Kokini, J. L., “Chapter 2 Advances in 3D Numerical Simulation of Viscous and Viscoelastic Mixing Flows", in Food Engineering Interfaces, Aguilera, J. M., Simpson, R., Welti-Chanes, J., Bermudez-Aguirre, D., Barbosa-Canovas, G. (Eds.), Springer New York, New York, p. 19–44 (2011)Search in Google Scholar

Vyakaranam, K. V., Kokini, J. L., “Prediction of Air Bubble Dispersion in a Viscous Fluid in a Twin-Screw Continuous Mixer Using FEM Simulations of Dispersive Mixing", Chem. Eng. Sci., 84, 303–314 (2012), DOI:10.1016/j.ces.2012.07.01410.1016/j.ces.2012.07.014Search in Google Scholar

Willis, R.: Principles of Mechanism, Cambridge University Press, Cambridge (1841)Search in Google Scholar

Winck, J., Kilzer, A. and Frerich, S., “CO2-Assisted Foaming of PLA by Using a Planetary Roller Extruder for an Enhanced Mass and Heat Transfer", Proceedings of the 16th International Conference on Advances in Foam Materials & Technology, Montreal, Canada (2018)Search in Google Scholar

Xu, B., Liu, Y., He, L., Chen, J. and Turng, L.-S., “Numerical Study of Mixing Dynamics inside the Novel Elements of a Corotating Nontwin Screw Extruder", Adv. Polym. Technol., 54, 107 (2017), DOI:10.1002/adv.2192310.1002/adv.21923Search in Google Scholar

Zhang, X.-M., Feng, L.-F., Chen, W.-X. and Hu, G.-H., “Numerical Simulation and Experimental Validation of Mixing Performance of Kneading Discs in a Twin Screw Extruder", Polym. Eng. Sci., 49 (9), 1772–1783 (2009), DOI:10.1002/pen.2140410.1002/pen.21404Search in Google Scholar

Zhu, X. Z., Wang, T. S. and Wang, G., “Evaluations of Flow and Mixing Efficiency in the Kneading Discs of a Novel Tri-Screw Extruder", J. Appl. Fluid Mech., 9 (1), 51–60 (2016), DOI:10.18869/acadpub.jafm.68.224.2336610.18869/acadpub.jafm.68.224.23366Search in Google Scholar

Received: 2020-12-17
Accepted: 2021-03-21
Published Online: 2021-11-16

© 2021 Walter de Gruyter GmbH, Berlin/Boston, Germany

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