(452g) Predicting Temperature Profile of Partially Filled Twin Screw Extruder Using 3D Multiphase CFD Model

Due to their flexible and modular screw elements design, twin-screw extruders (TSEs) are widely used in many operations that involve compounding, (dispersive and distributive) mixing, and de-volatilization. Screw design and selection is a non-trivial task, even more so during scale up. Typically, detailed experimentation is required to come up/select the proper screw design. Detailed three dimensional computer modeling on the other hand, has been lacking since it is rather challenging to model the partially filled twin screw system. Additional modeling complication arise due to the continuously changing flow geometry during the rotation as well as the tight gaps between the intermeshing screw elements as well as between the screw elements and the barrel wall. Typically, one or two dimensional model representations have been implemented instead. However, these reduced dimension models do not provide the full and complex details that are present in such complex equipment.

In the current work, a new modeling approach based on the overset mesh algorithm was implemented to model the co-rotating twin screw system. The twin screw system was partially filled and hence the model represented both the polymer as well as the air inside the system (multi-phase model). The model is created on a preheated silicone fluid processed in a co-rotating, fully intermeshing TSE. Results of model predicted temperature profiles are reported.