Development of Prediction Technique of Materials Behavior in Twin Screw Extruders Using the Particle Simulation Method
Tetsuharu Tsuji, Toshihisa Kajiwara, Kazumori Funatsu
Department of Chemical Engineering, Kyushu University
JAPAN

Keywords: Particle Method, Twin Screw Extruder, Simulation

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We have been developing the simulation code of materials behavior in twin screw extruder based on the formation of particle method or discretized element method. It contains the solid conveying, melting and melt pumping zones in unfilled states. Now we have developed 2-D code and confirmed the qualitative reliability, and then continue to extend the 3-D code.
At first, we have developed 2-D unsteady and isothermal polymer melt flow simulation code in unfilled state of TSEs using particle method. The analysis was performed at various degrees of material filling and rotational speeds and then we discussed interface length and frequency of interface renewal. We found that influence of rotational speed is very small for increase of the interface length because viscosity term is more dominant comparing with the inertia and gravity terms. Interface length takes a maximum value at 40 % filling. When the time being at the interface was calculated, the time of particles at leak flow from tip clearances were long and number of particle existing at interface for a long time decreased as material filling increased because leak flow took in large lump as soon as leak flow took place.
We also analyzed melt flow containing solid particles and succeeded to show the flow behavior in TSEs. We will extend this code to non-isothermal and represent melting process.