The use of global mixing indices to assess mixing efficiency in single screw extrusion

Abstract

Mixing indices can be derived from descriptions of morphology evolution of liquid-liquid or solid-liquid systems coupled to computations of flow and temperature along a plasticating screw (thus, including in the analysis the melting and melt conveying stages). In the case of liquid-liquid systems, distributive mixing depends essentially on droplet stretching and residence time, while dispersion takes into account the opposed effects of drop break-up and coalescence. Distributive mixing of solids-liquid systems depends on residence time and location (calculated via entropy), while dispersive mixing considers rupture and erosion phenomena.