Simulation of distributive mixing inside mixing elements of co-rotating twin-screw extruders

The mapping method is a powerful simulation tool to optimize distributive mixing inside periodic mixers. Recently, a new approach of the mapping method was introduced to simulate distributive mixing inside dynamic, complex geometries in an open flow system (twin-screw extruders). Here we apply this approach of the mapping method to different mixing elements, both kneading and screw mixing element (SME), inside a twin-screw extruder. The accuracy of the mapping method depends on the accuracy of the velocity field and these accurate 3D velocity fields are here calculated using an extended finite element method. For the kneading elements a variety of staggering angles have been investigated, and the mixing performance of the SME element is compared with a standard conveying element. To better quantify the mixing performance, additional parameters like particle trajectories, residence time distribution and the volume-integrated, intensity of segregation are used as a mixing measure.