The Evaluation of Mixing Characteristics of Dulmage Screw

Abstract:

The mixing performance of Dulmage screw was studied experimentally and numerically. In the experiment, Low density polyethylene and red colored mastebatch were mixed and extruded by using Dulmage screw or Full Flight screw. And then, the degree of color uniformity was measured on the cross-section of the extrudate. The masterbatch was distributed more uniformly on the cross-section of Dulmage screw than that of Full Flight screw. The degree of color uniformity for Dulmage screw was about two times higher than that for Full Flight screw. In the numerical analysis, the flow pattern of the masterbatch in the screw channel of Dulmage screw was visualized by means of particle tracking technique. The degree of the distribution of the masterbatch was quantified as the information entropy. The information entropy at the outlet of the screw changed periodically with the screw rotation speed. Furthermore, the masterbatch circulated between the screw surface and the barrel surface in the fin section, consequently the degree of the distribution of the masterbatch changed periodically. In case the masterbatch was distributed uniformly along the channel depth at the outlet of the fin section, the information entropy at the outlet of the screw became high. The result shows the mixing performance of Dulmage screw strongly related to the degree of the distribution of the masterbatch at the outlet of the fin section.

• Periodical: Advanced Materials Research (Volume 747)
• Pages: 769-772
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.747.769
• Online since: August 2013
• Authors: Koichi Kimura, Yusuke Itamochi, Hideki Tomiyama
• Keywords: Distribution, Dulmage Screw, Mixing, Screw, Single Screw Extruder

References

[1] C. Rauwendaal, Polymer Extrusion, HANSER Publication, (2001).

[2] F.E. Dulmage, U. S. Patent 2, 453, 088.

[3] K. Alemaskin, I. Manas-Zlocower, M. Kaufman, Polym. Eng, Sci., 45, 1031, (2005).