PhD subjects

2 sujets INAC

Dernière mise à jour : 12-09-2018


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• Thermal energy, combustion, flows

 

Inertial Confinement and Centimetric Cavity Collapse

SL-DRF-18-0218

Research field : Thermal energy, combustion, flows
Location :

Service des Basses Températures

Laboratoire Cryogénie Fusion

Grenoble

Contact :

Jérome DUPLAT

Starting date : 01-09-2017

Contact :

Jérome DUPLAT

Université Grenoble Alpes - DRF/INAC/SBT/LCF

04 38 78 64 89

Thesis supervisor :

Jérome DUPLAT

Université Grenoble Alpes - DRF/INAC/SBT/LCF

04 38 78 64 89

In the frame of the research on the inertial confinement to obtain the nuclear fusion, we intend to study the collapse dynamics of large nearly-void spherical bubble inside a liquid, provoking the inertial confinement of the matter trapped inside the cavity.

This process is similar to sonoluminescence experiment or to inertial confinement fusion experiement. However, our original setup allows to work at larger length and time scales,

and then allow the direct observation of all thermodynamical and hydrodynamical phenomena.



Preliminar experiments indicates that temperature higher than 20000 K can be reached, and maybe much more.



The experimental work will be a base for developing physical models.

Contribution to thermal modelisation and oscillating flow dynamics applied to pulse tube cooler

SL-DRF-18-0851

Research field : Thermal energy, combustion, flows
Location :

Service des Basses Températures

Laboratoire Cryoréfrigérateurs et Cryogénie Spatiale

Grenoble

Contact :

Sylvain MARTIN

Shihe XIN

Starting date : 01-09-2018

Contact :

Sylvain MARTIN

CEA - DRF/INAC/SBT/LCCS

+ 33 4 38 78 31 71

Thesis supervisor :

Shihe XIN

INSA Lyon - CETHIL (UMR 5008 INSA/CNRS/UCBL) Groupe Transferts Convectifs

04.72.43.70.77

The Low Temperature Laboratory (SBT) from CEA/INAC is involved in technological cryogenic research in a large temperature range from 120 K down to few tens of millikelvins. CETHIL (CNRS, INSA, UCBL) has a strong expertise in numerical simulation for systems involving flow study coupled to thermal transfer.



In SBT, the LCCS team (Cryocoolers and space cryogenics lab) develops small cryocoolers ranging from 50 mK up to 50 K. Among those developments, the pulse tube is a key component in the team. Based on the Stirling thermodynamic cycle, it allows to reach temperature between 4 K and 100 K with helium. They are used in satellite for earth observation (MTG, Met-Image) around 50 K. For space observation mission (ATHENA/X-IFU), a system able to reach 15 K has been developed and a prototype demonstrates an ultimate temperature of 4 K.

In CETHIL, the involved team has a strong expertise in numerical simulation of thermal transfer in fluid media. They are using CFD simulation and have developed their own numerical simulation dedicated to thermal studies. The team is also using massive parallel computation.



Based on the expertise of the 2 laboratories, the aim of the internship is to develop a model of a pulse tube that allows to cover the temperature range of 100 K – 4 K. A better comprehension of the phenomena inside the pulse tube is expected. Hence, a faster improvement of the performances. A combination of thermal modelling and oscillating flow dynamics for real gas is needed. The tool shall also be able to size multi-stage systems (Dual stage pulse tube, 15 K PT …). The model will be compared to experimental results already available in SBT but also on dedicated test bench to validate some sub-system of a pulse tube cooler. The test bench shall be developed during the PhD.



The PhD thesis will be both in Lyon at CETHIL laboratory for numerical simulation and in Grenoble at SBT for the experimental time.



The candidate shall have a master degree in the field of the thermal study, mechanic or energetic. He shall have background in thermodynamics, thermal transfer and simulation with an interest for thermal machines and physics.

 

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