Effect of different viscosity on optimal shape of static mixers for food industry

Mixing is a common process in food industry, and in particular it is interesting to develop optimal mixers in order maximize fluid mixing and minimize energy consumption by reducing the viscous dissipation effects. Although many studies and results had been presented in literature for both batch and static mixers (Rauline et al. 2000 and Mutsakis et al. 1986 for a review) the lack of a developed theory of instability for non-Newtonian fluids, quite common in the food industry, leaves the problem open. In this work, the Optimal Shape Design (OSD) technique was applied to design static mixers for a Newtonian (i.e., water) and pseudoplastic (i.e., peach puree) liquid. Results show for the Non-Newtonian case, a classical coaxial static mixer, the application of OSD allows a sensible improvement of the performances, while in the Newtonian case (High Efficiency Vortex mixer), due to the different design approach, the overall effects are negligible