Jovani L. Favero

Viscoelastic fluid analysis in internal and in free surface flows using the software OpenFOAM

Synthetic polymer products are of great importance in several industrial sectors, such as for production of packaging, parts of appliances, electronics, cars and food processing industries. Due to the increasing demand for this kind of material, reduction of waste and increase of quality has become a key issue in polymer industry. In this sense modeling and simulation of processing operations appears as a fundamental tool, leading to better understanding of how the rheological properties of polymers affect their processability and final product quality, and reducing time and costs related to the development of processes and products. This work presents some basic results that aims to validate a developed methodology for internal viscoelastic fluid flows, which was developed in a previous work in the OpenFOAM computational fluid dynamics package and also will be showed a extension of this methodology for analysis of free surface viscoelastic fluid flows, using the VOF methodology. A classical flow phenomena used in the rheology literature to present the concept of viscoelastic effects was simulated, i.e., the die swell experiment. The results obtained using Giesekus model showed the great potential of the developed formulation, once phenomena observed experimentally were reproduced in the simulations.

Viscoelastic Flow Simulation: Development of a Methodology of Analysis Using the Software OpenFOAM and Differential Constitutive Equations

Abstract Viscoelastic fluids are of great importance in many industrial sectors, such as in food and synthetic polymers industries. The rheological response of viscoelastic fluids is quite complex, including combination of viscous and elastic effects and highly nonlinear viscous and elastic phenomena. This work presents a new Computational Fluid Dynamics (CFD) tool for the simulation of viscoelastic fluid flows, which consists of a viscoelastic fluid module to be used with OpenFOAM CFD package. The main reasons for using OpenFOAM in the development of this tool are its characteristics with relation to flexibility to deal with complex geometries, unstructured and non orthogonal meshes, moving meshes, large variety of interpolation schemes and solvers for the linear discretized system, and the possibility of data processing parallelization. Several constitutive equations, such as Maxwell, UCM, Oldroyd-B, Giesekus, Phan-Thien-Tanner (PTT), Finitely Extensible Nonlinear Elastic (FENE-P and FENE-CR) and some derivations of Pom-Pom were implemented, in single and multimode form, and in this work the results are presented with the Giesekus model. The proposed methodology was validated by comparing its predictions with experimental and numerical data from the literature for the analysis of a planar 4:1 contraction flow.

Simulation of Free Surface Viscoelastic Fluid Flow Using the viscoelasticInterFoam Solver

The understanding of polymeric fluids flows is of essential importance for several industry sectors, including plastic and food processing industries. The rheological response of viscoelastic fluids is quite complex, including combination of viscous and elastic effects and highly non-linear viscous and elastic phenomena. In a previous work we presented a solver for internal viscoelastic fluid flows, called viscoelasticFluidFoam, which was developed with the OpenFOAM computational fluid dynamics package and validated with experimental and numerical data from the literature for the analysis of a planar 4:1 contraction flow. In the present work will be tested the extension of the viscoelasticFluidFoam solver to the viscoelasticInterFoam solver used for analysis of free surface viscoelastic fluid flows using the VOF methodology. A classical die swell flow phenomena used in the rheology literature to present the concept of viscoelastic effects was simulated. The results obtained using Giesekus model showed the great potential of the developed formulation, once all phenomena observed experimentally were reproduced in the simulations.