Fluid flow and distributive mixing analysis in the cavity transfer mixer

In the polymer industry good mixing is essential to guarantee the characteristics of finished products. However, optimizing mixing devices is often difficult, because mixing mechanisms are the result of the complex interaction between the moving elements and the non-Newtonian fluids used. Full three-dimensional simulations are computationally expensive and the complexity of the problem is often split into approximated subproblems. The present work focuses on a simplified two-dimensional model of the Cavity Transfer Mixer, investigating stretching and folding mixing actions. Several geometrical and functioning parameters, such as cavity speed, cavity shape, inter-cavity distance, rotor-stator clearance, and fluid rheology are varied. Mixing is analysed in terms of Poincar\'e maps and by simulating the evolution of fluid blobs. The inter-cavity distance
is found to play a major role, enabling, and governing the stretching actions inside the mixing device.