36D-3 |
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B. K. ASHOKAN, L. M. Fanning, and J. L. Kokini. Dept. of Food Science, Rutgers, The State Univ. of New Jersey, Center for Advanced Food Technology, 65 Dudley Rd., New Brunswick, NJ 08901-8520 Numerical simulation of complex geometries such as a continuous mixer to predict mixing behavior and alternate mixing geometries is now possible due to advanced numerical strategies and greater computational capacity. But the accuracy of such simulations can be improved and comparisons to experimental measurements of velocity using Laser Doppler Anemometry (LDA) at particular locations in a continuous mixer provide a convenient measure of estimating the accuracy of the simulation. The objective of this work is to obtain an accurate prediction of the velocity components in a continuous mixer using 3D Finite Element Methods (FEM) simulation to examine the flow and mixing in a 2” Readco Continuous Processor and compare the predictions to results obtained using LDA. FEM simulations using generalized Newtonian fluid rheology were performed with Polyflow (Fluent Inc.), which uses a mixed Galerkin formulation of the isothermal governing equations of motion and continuity. Increasingly complex 3D geometries were developed to accurately represent the geometry and flow conditions in the continuous mixer and the predictions were compared with the velocities measured by LDA. Predictions by numerical simulation and observed experimental velocities in a plane perpendicular to the flow agreed well at all representative points with in the mixer. The predicted data for the velocity component in the direction of flow required careful definition of boundary conditions to obtain agreement with experimental data. The addition of paddles to the simulation geometry in the direction of flow improved the description of the boundary conditions by allowing the flow to develop sufficiently. The successful simulation of the continuous mixer geometry in 3D provides valuable insight into the mixing processes involved, and paves the way for efficient scale-up or redesign of mixers.
Session 36D, Food Engineering: Rheology
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |