Flow Simulations for the Design of Extrusion Systems Using OpenFOAM

Extrusion systems are often used to produce car tire components. For the design of these extrusion systems, simulations are performed at VMI using Computation Fluid Dynamics (CFD). The rheological properties of the extruded rubber compound, material model, meshing of the domain, numerical scheme, etc., affect the reliability of the simulations. Thus, it is of paramount importance to develop an algorithm that is able to correctly predict the behavior of rubber during extrusion.
A commercial CFD software tool is currently used at VMI to simulate the flow of rubber out of an extruder. However, as the demand for a more accurate velocity and pressure prediction is always on the table, we are eager to investigate the capabilities of an open-source software tool due to its flexibility and innovative nature. OpenFOAM is an open-source CFD software that has proven to be reliable for this task. It contains, among other things, different models for generalized Newtonian fluids, realistic boundary conditions and the flexibility for new implementations if needed.

Objective
The main objective of this assignment is to develop an algorithm – using the open-source software OpenFOAM – that is able to replicate the results of the currently used commercial software. The student will find the optimal parameters needed for the software to simulate a realistic extrusion process. As a challenge, the student can explore the effect of realistic boundary conditions, such as a stick-slip model for the walls inside the die.

Assignment
The student will start by learning about the meshing tools available in OpenFOAM, such as blockMesh and snappyHexMesh. Then, the student will do a review study about the equations of motion that describe the fluid, followed by a review of the numerical methods and solvers implemented in the software, the material models, and initial and boundary conditions. As the project advances, the student will learn about post-processing tools, such as the open-source software Paraview, in order to visualize the obtained fields (mesh, pressure, velocity, viscosity and temperature), see for instance Fig. 1. Additionally, the use of a different software (Matlab or Spyder for example) will be decided to be able to make plots and/or videos that help explain the obtained results.

Report
The graduation report should contain a literature review about the Finite Volume Method employed by OpenFOAM, a description of the equations solved by the software, including the model used to simulate a generalized Newtonian fluid with high viscosity. More importantly, the student should write an algorithm describing the commands to be followed in OpenFOAM, as well as the optimal parameters found, in order to standardize the process for future usage as a design tool.