Parametric Study of the Mixing Efficiency in a Kneading Block Section of a Twin-screw Extruder

Abstract Twin-screw extruders are often used to distribute and disperse additives into polymers. The mixing efficiency of the extruders highly depends on the geometry of the kneading blocks of the mixing section. In this paper, the impact of some geometrical parameters, such as the stagger angle and the width of the discs, are investigated by three dimensional time dependent finite element calculations. Results are obtained with the finite element software Polyflow. The robustness and the accuracy of the mesh superposition technique is evaluated. It appears that conclusions obtained by the numerical experiments can be used to improve the geometry of the kneading blocks. The mixing efficiency is evaluated by comparing the residence time and the total shear distributions of a large set of virtual particles launched in the flow domain.

[1]  J. White,et al.  Flow Visualization and Residence Time Distributions in a Modular Co-rotating Twin Screw Extruder , 1994 .

[2]  S. Bakalis,et al.  Applications of laser Doppler anemometry in understanding food processing operations , 1997 .

[3]  M. Booy.  Isothermal flow of viscous liquids in corotating twin screw devices , 1980 .

[4]  H. Barnes,et al.  An introduction to rheology , 1989 .

[5]  Kazumori Funatsu,et al.  3‐D numerical simulations of nonisothermal flow in co‐rotating twin screw extruders , 2000 .

[6]  Marcel Crochet,et al.  Finite-element simulation of mixing .1. Two-dimensional flow in periodic geometry , 1997 .

[7]  David I. Bigio,et al.  Parametric study of a 2-D model of the nip region in a counter-rotating, non-intermeshing twin screw extruder , 1991 .

[8]  Y. Rubin,et al.  Analysis of Mixing in Corotating Twin Screw Extruders through Numerical Simulation , 2000 .

[9]  Christopher W. Macosko,et al.  Rheology: Principles, Measurements, and Applications , 1994 .

[10]  S. Jaffer,et al.  Experimental validation of numerical simulations of the kneading disc section in a twin screw extruder , 2000 .

[11]  K. Funatsu,et al.  Mixing mechanism of three‐tip kneading block in twin screw extruders , 2000 .

[12]  Ica Manas-Zloczower,et al.  Mixing and Compounding of Polymers: Theory and Practice , 1994 .

[13]  J.J. Shea.  Plastic Compounding Equipment and Processing , 1998, IEEE Electrical Insulation Magazine.

[14]  Mukund V. Karwe,et al.  Velocity distributions and volume flow rates in the nip and translational regions of a co-rotating, self-wiping, twin-screw extruder , 2002 .

[15]  O. S. Galaktionov,et al.  A mapping approach for three-dimensional distributive mixing analysis , 2001 .

[16]  P. V. Danckwerts.  The Difinition and Measurement of Some Characteristics of Mixtures , 1953 .

[17]  M. L. Booy,et al.  Geometry of fully wiped twin-screw equipment , 1978 .

[18]  Leon P.B.M. Janssen,et al.  Flow patterns in the calender gap of a counterrotating twin screw extruder , 1987 .

[19]  Philippe A. Tanguy,et al.  Adaptive finite element simulations of fluid flow in twin-screw extruders , 2003, Comput. Chem. Eng..

[20]  Edward J. Kramer,et al.  Materials Science and Technology, Materials Science and Technology - A Comprehensive Treatment: Index of Volume 1-18 , 1998 .

[21]  Andrew N. Hrymak,et al.  Numerical simulation of pressure and velocity profiles in kneading elements of a co‐rotating twin screw extruder , 2000 .

[22]  James L White,et al.  Modelling Flow in an Intermeshing Co-rotating Twin Screw Extruder: Flow in Kneading Discs , 1987 .

[23]  J. Ottino.  The Kinematics of Mixing: Stretching, Chaos, and Transport , 1989 .

[24]  Michel Fortin,et al.  Mixed and Hybrid Finite Element Methods , 2011, Springer Series in Computational Mathematics.

[25]  T. Osswald,et al.  Comparative study of rhomboidal mixing sections using the boundary element method , 2000 .

[26]  Thierry Avalosse,et al.  Numerical simulation of distributive mixing in 3‐D flows , 1996 .

[27]  T. Kwon,et al.  Numerical and experimental studies of the flow in the nip region of a partially intermeshing co‐rotating twin‐screw extruder , 1990 .

[28]  Kazumori Funatsu,et al.  3-D non-isothermal flow field analysis and mixing performance evaluation of kneading blocks in a co-rotating twin srew extruder , 2001 .

[29]  R. Erdmenger,et al.  Mehrwellen-Schnecken in der Verfahrenstechnik† , 1964 .