Étude expérimentale et modélisation de la cokéfaction des huiles aéronautiques

The aeronautics sector must rapidly evolve to further improve aircraft energy efficiency. This involves the evolution of fluids, the modification of system architectures and, of course, the optimization of these two items to ensure a safe operation. The degradation of aeronautical oils is one topic that has to be addressed. It may be associated with an oxidation mechanism, or simply with thermal degradation. Both processes can lead to the formation of deposits and alteration of system operability (cooling or lubrication performance decrease, impact on filtration, etc.). These processes are widely discussed in the literature for simple hydrocarbons such as fuels, but the degradation of aeronautical oils remains poorly documented.
The thesis aims at studying experimentally the degradation processes of aeronautical oils in extreme environments, to better understand operating conditions leading to deposit formation and the associated key descriptors (e.g. oil chemistry, thermodynamic conditions or materials present). Following an in-depth literature review on this topic, the experimental work will aim at identifying the relevant real and model fluids, then implement the operating conditions suited to deposit formation and finally integrate the desired physicochemical analyses. These steps will help generate a database needed to identify sensitive descriptors for the process under investigation. 
The PhD student will acquire a solid experimental experience through the various steps proposed, while developing his or her skills in the field of fluid reactivities.
 

Mots-clés : Huile aéronautique, turbomachine, dégradation thermo-oxydative, cokéfaction, dépôts