Development of CFD multiphysics solvers for plastic waste recycling applications

IFP Energies nouvelles (IFPEN) est un acteur majeur de la recherche et de la formation dans les domaines de l’énergie, du transport et de l’environnement. De la recherche à l’industrie, l’innovation technologique est au cœur de son action, articulée autour de quatre priorités stratégiques : Mobilité Durable, Energies Nouvelles, Climat / Environnement / Economie circulaire et Hydrocarbures Responsables.

Dans le cadre de la mission d’intérêt général confiée par les pouvoirs publics, IFPEN concentre ses efforts sur :

• l’apport de solutions aux défis sociétaux de l’énergie et du climat, en favorisant la transition vers une mobilité durable et l’émergence d’un mix énergétique plus diversifié ;
• la création de richesse et d’emplois, en soutenant l’activité économique française et européenne et la compétitivité des filières industrielles associées.

Partie intégrante d’IFPEN, l’école d’ingénieurs IFP School prépare les générations futures à relever ces défis.

Development of CFD multiphysics solvers for plastic waste recycling applications

Plastics recycling is a huge environmental challenge for future years, especially as the worldwide production of plastics is increasing continuously and will triple by 2050. Today in Europe, only 10% of the plastic materials enters the recycle stream.

Chemical recycling pathways have been investigated since several years at IFPEN. This research has led the developments of new processes and new experimental installations to test them. However, polymer chemical recycling presents new challenges and almost every unit operation must be specifically designed. Lots of uncertainties remain unsolved and need to be addressed, particularly in the simulation of polymer processes. CFD of polymer and solvent mixing in screw extruders is a rather challenging task, due to meshing issues in overlapping geometries, due to complex multiphysics involving viscous dissipation, heat transfers, mixing of fluids with high viscosity ratio (solvent and melted polymer), mostly non-Newtonian, and chemical reaction.

Description :

The overall objective of the project is to develop a numerical twin model for the simulation of chemical processes involving plastics, like for example solvent and polymer mixing in screw extruders. Existing (or new) CFD solvers will need to be assessed (or developed) in order to solve the complex multiphysics involved in this type of simulations.

The general approach will rely on developments based on the opensource software OpenFOAM. OpenFOAM is free of charge and provides full access to all its sources, making it a valuable and flexible platform for the implementation, testing and integration of new models.

After being trained to the OpenFOAM suite, this internship will have the following main objectives:

• Train on CFD solvers for non-Newtonian fluids, taking in hands former works
• Assess (or develop) CFD solvers handling mixing of two miscible fluids of high viscosity ratio. The two fluids have highly different viscosities (μ₁ / μ₂ ≈ 10⁶ ).
• Assess (or develop) CFD solvers handling heat transfers due to viscous friction in the system

Developments will be tested on benchmark cases taken from the literature. Further tests will be conducted on systems meeting IFPEN requirements used in polymer recycling processes.

Opportunity to continue with a PhD on the same subject.

Required profile :

• English or French, OpenFOAM, curiosity, enthusiasm, autonomy.
• Strong background in fluid mechanics and CFD, programming in C++ and shell script.
• Knowledge in chemical engineering and polymers would be a plus.