Description du sujet de thèse

At the CNRS, on the Futuroscope site, the PPrime Institute is recruiting a doctoral student to study the numerical modeling of overlapping piston ring seals in static, semi-static and dynamic operating conditions as part of the ANR/AEROSEAL-funded research project.

This thesis is being conducted within the framework of a partnership between the PPRIME Institute, Safran Aircraft Engines and CETIM, and the AEROSEAL chair, whose objective is to improve knowledge of aeronautical sealing.

Overlapping piston ring seals are used in numerous aeronautical applications, both civil and military. Their primary function is to ensure an airtight and/or oiltight seal between two pressurized engine cavities.

These rings can operate in different configurations:
- Static: the ring is fixed in its bore and provides a seal between two static parts (without relative movement between the two parts)
- Semi-static: the ring can move axially in its bore over a very short distance and provides a seal between two static parts
- Dynamic: the ring can move axially in its bore over a very short distance and provides a seal between two parts in relative movement (such as a "piston/bore" or "rotor/stator" system).

The estimation of leakage rates is currently carried out using an analytical approach that does not take into account the physicochemical properties of the ring, the interfacing parts, or their surface conditions.

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1-The objectives of the thesis are:
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- To understand fluid flows through inter-shaft seals
- To quantify leakages at the piston ring/bore and piston ring/rotor interfaces and at the clearance level
- To define sizing criteria
- To optimize the piston ring geometry (axial/radial dimensions; sealing clearance, surface finish, materials, etc.) for different application cases.

Refined numerical modeling of the seal ring will enable the implementation of strategies to improve its operating conditions.

2-Task Description:
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- State of the art / monitoring of single- and two-phase fluid flow modeling
- Modeling of single- and two-phase flows through sealing rings in static configurations
- Modeling of single- and two-phase flows through sealing rings in semi-static configurations
- Modeling of single- and two-phase flows through sealing rings in dynamic configurations
- Exploitation of experimental test campaign results
- Comparison of calculations/tests and validation of the numerical model

The candidate must hold a Master's degree in Mechanical or Aeronautical Engineering or in Materials Science with good training in numerical modeling of continuous media and a programming language.

Contexte de travail

The PhD student will be based at the Pprime Institute / ENSMA (pprime.fr) and will participate in project progress meetings at the sites of industrial partners Safran Aircraft Engines and CETIM Nantes.

Le poste se situe dans un secteur relevant de la protection du potentiel scientifique et technique (PPST), et nécessite donc, conformément à la réglementation, que votre arrivée soit autorisée par l'autorité compétente du MESR.

Contraintes et risques

- Doctoral School: enrolment at the University of Poitiers MIMME.
- Short trips within France and abroad are to be expected.