Nucleate boiling: heat transfer mapping and study of mechanisms at wall-fluid interfaces

NUCLEATE BOILING: HEAT TRANSFER MAPPING AND STUDY OF MECHANISMS AT WALL-FLUID INTERFACES Réf ABG-102161 Sujet de Thèse 06/01/2022 Contrat doctoral Institut FEMTO-ST Lieu de travail Besançon - Bourgogne-Franche-Comté - France Intitulé du sujet Nucleate boiling: heat transfer mapping and study of mechanisms at wall-fluid interfaces Champs scientifiques * Sciences de l’ingénieur Mots clés nucleate boiling, heat transfer, microfabrication, sensors DESCRIPTION DU SUJET RESEARCH UNIT : thesis CO-DIRECTED by the UNIVERSITY OF BOURGOGNE FRANCHE-COMTÉ and the UNIVERSITY OF AIX-MARSEILLE: * FEMTO-ST institute, 15 B avenue des Montboucons, 25030 BESANCON cedex (University of Bourgogne Franche-Comté), FRANCE * IUSTI laboratory, 5 rue Enrico Fermi, 13453 MARSEILLE Cedex 13 (University of Aix-Marseille), FRANCE FUNDING: Duration of 3 years, ANR funding (French National Research Agency) CONTEXT : This thesis is part of the TraThI project (Thermal Transfer at Interfaces) labelled by the ANR in 2021. It aims to study heat transfer at the transition between convective and nucleated boiling regimes, at micro and macro scales. This ANR is a partnership between the institutes IUSTI, FEMTO-ST and IMFT (in France) and LTT-UL (Slovenia). The objective of the project is to understand in detail the mechanisms at the wall-fluid interfaces in order to develop new strategies to improve the heat transfer between a fluid and a wall. The project anticipates the challenges to be met in the fields of energy technologies and industry of the future, where the flow densities are an order of magnitude higher than those accessible by current techniques. DETAILED PRESENTATION OF THE SUBJECT: The thesis will be mainly experimental and will focus on performing nucleate boiling experiments (Tadrist et al., 2020). The objective of the thesis will be to study the mechanisms at the solid-liquid-vapor interfaces in order to propose new strategies capable of subtantially increasing the heat flux densities between a wall and a fluid. Solutions capable of continuously renewing the fluid layer (a few micrometers thick) adjacent to the wall would allow to substantially increase the heat transfer. The study of heat transfer in the presence of wall nucleation will allow to evaluate the heat fluxes transferred and to identify the mechanisms at the origin of the intensification of heat transfer in this regime. Part of the thesis work will concern the structuring of the surfaces and the development of temperature and flow sensors. Indeed, in order to control the nucleation and quantify the heat exchanges, the nucleation surface will be controlled and instrumented by sensors thanks to microfabrication processes in clean room (Zribi et al., 2018, Mokadem et al. 2019). Several approaches for surface texturing will be considered (chemical etching, chemical vapor deposition...) some of which have already shown promising results (Zakšek et al., 2020). In addition, temperature microsensors (Lanzetta et al., 2011), associated with optical measurements (Carvalho et al., 2014), will allow mapping velocities and temperatures in the liquid (especially near the surface). The obtained measurements will allow the creation of a database. This will be used to develop a numerical code by a collaborator (post-doc) recruited in the framework of the TraThI project. A complementary experimental study (convective boiling) will be conducted by another PhD student with the other partners of the project (IMFT/LTT-UL). The person recruited on this thesis will thus have to work in close collaboration with the various partners of the TraThI project. RÉFÉRENCES : Barthes et al. (2007) Europhysics Letters (EPL), 10.1209/0295-5075/77/14001 Carvalho et al. (2014) Mechanics & Industry, 10.1051/meca/2014021 Lanzetta et al. (2011) CRC Press, Taylor and Francis, 95-142, 10.1201/b10918 Mokadem et al. (2019) Proc. of 19th International Metrology Congress, Paris hal-02366775 Tadrist et al. (2020), International Journal of Heat and Mass Transfer, 10.1016/j.ijheatmasstransfer.2020.119388 Zakšek et al., (2020) Nanoscale and Microscale Thermophysical Engineering, 10.1080/15567265.2019.1689590 Zribi et al. (2018) European Physical Journal Applied Physics, 10.1051/epjap/2018170295 PRISE DE FONCTION : 04/07/2022 NATURE DU FINANCEMENT Contrat doctoral PRÉCISIONS SUR LE FINANCEMENT ANR (French National Research Agency) PRÉSENTATION ÉTABLISSEMENT ET LABO D'ACCUEIL Institut FEMTO-ST The PhD is co-supervised by the FEMTO-ST INSTITUTE (BESANÇON, FRANCE) and the IUSTI LABORATORY (MARSEILLE, FRANCE) FEMTO-ST is a public research institute associated with the CNRS, in the fields of engineering and applied physics. The FEMTO-ST Institute “Franche-Comté Electronics Mechanics Thermal Science and Optics – Sciences and Technologies”, is a joint research institution, which is under the quadruple authority of the Université de Franche-Comté (UFC), the Centre National de la Recherche Scientifique (CNRS), the Ecole Nationale Supérieure de Mécanique et Microtechniques (ENSMM) and the Université de Technologie Belfort-Montbéliard (UTBM). Today, in FEMTO-ST's scientific departments and general services, we count a total staff of more than 700. The Institute is organized into seven departments : * Automatic Control and Micro Mechatronic Systems * Department of Computer Science and Complex * Energy * Applied Mechanics * Micro Nano Sciences and Systems * Optics * Time-Frequency The IUSTI LABORATORY is a joint research unit affiliated with the CNRS and Aix Marseille University (UMR 7343). The laboratory focuses on engineering sciences with research in mechanics and energetics related to various applications in industry, environment and health. The laboratory is structured in 4 research areas: * Physics of transfers * Compressibie flows, shock waves and interfaces * Combustion, Risks and civil engineering * Divided media and complex fluids SITE WEB : https://www.femto-st.fr/en PROFIL DU CANDIDAT DEGREE/DIPLOMA: Master II or Engineer level SCIENTIFIC SKILLS : * Very good in HEAT TRANSFER * Good in LIQUID-VAPOR PHASE CHANGE (nucleation, boiling...) * Good in SENSORS AND SIGNAL PROCESSING * Some skills/knowledge in NUMERICAL SIMULATION (Fluent, COMSOL...) * Some Skills/knowledge in MATERIAL SCIENCE * Some skills/knowledge in MICROFABRICATION WOULD BE APPRECIATED. OTHER CRITERIA : * Good level in ENGLISH * Ability to show INITIATIVE AND AUTONOMY * Have a strong taste for EXPERIMENTATION * BE GEOGRAPHICALLY MOBILE/FLEXIBLE (THESIS STRADDLING MARSEILLE AND BESANÇON; ANR partners in Toulouse and Slovenia...) Date limite de candidature 31/03/2022