Advanced Design of Industrial Mixers for Fluid Foods Using Computational Fluid Dynamics

Abstract This work focuses on discontinuous (batch) vertical fluid mixing systems for food fluids with particles. A properly designed mixing process has to provide two main results: a satisfactory homogeneity of the product and the preservation of the integrity of the solid particles. The main problem in the design of a mixer for fluid–solid suspensions is to identify the operating levers which act in order to optimize the performance of the process, while preserving the integrity of the pieces. The purpose of this work is to identify some structural and physical parameters that have the strongest influence on the performance of the mixing process, in order to obtain useful indications for the design of mixing systems. Different mixer designs were thus analyzed thanks to computational fluid dynamics simulations, from which some key performance indicators (KPIs) related to the effectiveness of the mixing process were obtained. An analysis of variance and a residual analysis were then performed in order to assess the significance of the influence of each input parameter (position of the rotor, fluid viscosity, and aspect ratio), on the individual KPIs and on the global performance of the mixer. From these analyses, some conclusions useful to choose an appropriate design solution for fluid mixers were derived.

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