Numerical design of distributive mixing elements

This paper presents a novel shape-optimization technique for the design of mixing elements in single-screw extruders. Extruders enable continuous production constant-cross-section profiles. Equipped with one or several screw-shaped rotors, extruders transport polymer particles towards outlet. Due to shear heating, melting is induced and melt stream created, which can be further processed. While many variants multi-screw exist, significant share all extrusion machines made up due their comparatively low operating costs complexity. reduced complexity yields economic benefits, extruders' capabilities, i.e., ability produce homogeneous material temperature distribution, suffer compared To compensate this shortcoming, so-called are added screw enhance by recurring flow reorientations. In view largely unintuitive characteristics melts, we present an optimization framework that allows designing these numerically based on finite-element simulations flow. reduce computational demand required shape complete section, only focus single element. advances three aspects numerical design: (1) A combination free-form deformation surface splines presented, allowing parameterize element's very few variables. (2) The concept linear-elasticity-based mesh update method deform domain without need remeshing demonstrated. (3) simple yet robust sensitive objective formulation assess distributive laminar flows measure interfacial area proposed.