(177ah) A Computational Fluid Dynamics (CFD) Simulation for Predicting the Processability of Polymers in a Twin-Screw Extruder with Experimental Validation

The industry has utilized the twin-screw extruder for large scale processing of various polymers, especially those that undergo compounding and mixing. The key to successfully manufacture these polymers is to identify the appropriate processing parameters. However, this entails numerous experiments that involve trial-and-error which is costly and time-consuming. In this study, Ansys Polyflow was used to build a CFD model that can predict polymer processability and extrusion process behaviors. This model is dependent on the manufacturing parameters: temperature profile, rotation speed, and feeding rate. Polypropylene (PP) and Polylactic Acid (PLA) properties and manufacturing conditions were used to run the model. The torque acquired from simulation is compared to experimental torque to validate the model. Hence, PP and PLA were extruded using a twin-screw extruder at different conditions to determine the optimum manufacturing conditions. This was used in the model to check if the agreement between simulated and experimental torque. The results showed that the model was in good agreement with experimental data with less than 10% difference. It is applicable in predicting the torque of polymers at different rotation speed and feeding rates where the barrel is completely filled and feed rates were sufficient. The processability of different polymer structures were also investigated by comparing the simulated and experimental torque of polystyrene (PS), and comparing its accuracy to PP and PLA. It showed that the model is applicable to semi-crystalline polymers. Overall, the processability of semi-crystalline polymers were predicted at different conditions. Further improvements to the model can extend its applicability to amorphous polymers and polymer composites.