LaBoMaP Directory PhD students HSM Team

KOULEKPA Koffi Samuel

Published on October 24, 2022 Updated on April 23, 2024


Thesis Topic

Study and optimisation of supercritical CO2- assisted machining
Etude et optimisation de l'assistance CO2 supercritique en usinage


The machining industry is constantly looking for new solutions to increase its productivity and the quality of the finished products while respecting environmental standards. Machining assistance is one of the most effective means; it increases chip removal rates while maintaining and improving the integrity of the cutting edges. But due to the ecological and health issues related to the use of flood coolants, new solutions must be explored to reconcile productivity and environmental issues. The ScCRYO2 project, of which this thesis is part, aims to study a new machining assistance, using supercritical carbon dioxide (scCO2), which combines cooling by phase change, and lubrication thanks to its properties of “green solvent”.
In this study, experiments are conducted on modelling and characterizing the properties of the scCO2 expansion by diverse dynamics fluids methods. Heat exchanges on a self-designed setup will help evaluate and improve the cooling abilities of the scCO2 for applications in machining.
New soluble lubricants are also investigated to exploit the "solvent" nature of scCO2, as green alternatives to current cutting oils (MQL, emulsions).
All these investigations are intended to be gathered in FEM simulation tools to either predict the influence of the scCO2 assistance on machining results or help finding optimal delivery configurations.
Long story made short (Three minutes thesis in French): see video.

Doctoral advisors



PhD in the frame of the scCRYO2 project: see video.



15th of September 2021

Expected end

30th of January 2025