Investigation of shear rates in twin-screw extruder using CFD-simulation

The twin screw extruder allows the incorporation of fibers and is used frequently for the compounding of reinforced materials. The advantage of the twin screw extruder is its modular design, where the screw can be adapted to the product by the different elements and barrels. In addition, the separate feeding of the matrix material and the fibers reinforce the wide use in compounding tasks. The compounding parameters during production have an influence on the fiber length in the compound. [1] In the state of the art, many models try to describe the fiber length decrease along the screw. The fiber length decrease along the extruder depends on many different parameters. The shear rate is one of the significant parameters. The output quality of a model depends on the input quality of the parameters. Therefore, this paper offers a different calculation of a resulting shear rate. Furthermore, the specialty of the twin screw extruder is calculated in the modeling for a fiber length decrease.