CFD study on special duty centrifugal pumps operating with viscous and non-Newtonian fluids

entrifugal pump design operating with special fluids (high viscosity, non-Newtonian, solid handling) is usually performed by considering water as the working fluid and then by applying empirical correction to the performance according to the fluid processed. CFD techniques allow the analysis of the impact of the fluid properties and the effectiveness of the design correction, rather than only relying on specific empirical data for each specific fluid. In this paper, a CFD analysis is performed on a large-size industrial food processing centrifugal pump originally designed for tomato paste. A model sensitivity analysis on the fluid constitutive law and on the flow regime modeling (laminar or turbulent) was performed. The CFD study showed that a fluid viscosity increase affects pump performances coherently with literature data. Then, pump curves and 3D flow structures obtained with non-Newtonian fluid are similar to those obtained with high viscous Newtonian fluids.