Modeling and optimization of tomato puree flow through a sudden expansion pipe joint using CFD

Abstract

This study investigates the flow physics of tomato puree through a sudden expansion pipe joint in a processing plant. Tomato is a widely cultivated vegetable crop. The food processing industry uses tomato juice and tomato paste to produce finished food products such as sauce, ketchup, and pulp. In terms of fluid flow physics, tomato puree exhibits non-Newtonian, shear-thinning behavior. Viscosity of tomato puree is modeled using non-Newtonian power-law model available in ANSYS FLUENT Computational Fluid Dynamics (CFD) modeling software. An important engineering result for this type of problem is major loss or friction power loss. Results are presented for friction power loss inside sudden expansion pipe flow geometrical configuration for a range of Reynolds numbers using the steady-state analysis. Zones of possible tomato puree mass accumulation are identified. The larger the accumulation zone, the worse is the engineering design. The rheological response of tomato puree following an accidental shutdown of the pumping mechanism is investigated through transient CFD simulations. Based on the findings of the analysis, an alternate geometrical configuration that may potentially avoid puree mass accumulation and reduce energy loss is suggested. The effects of key input parameters, including Reynolds number and rheological parameters governing viscosity, on the friction factor are quantified through empirical correlations, constituting a valuable outcome of the analysis.