Sébastien FERROUILLAT soutiendra son HDR (Habilitation à Diriger des Recherches) au LEGI, à Grenoble, le mardi 19 décembre à 9h00 en amphithéâtre K118 (Campus Site Bergès, Bât. K, 1209 rue de la Piscine, 38400 St. Martin d’Hères).
Title: Optimizing the thermal-hydraulic performance of heat exchangers
Abstract: Optimizing the thermal-hydraulic performance of heat exchangers is a key scientific and technical challenge in the drive for energy efficiency in the context of fossil fuels depletion and climate change. Following a description of heat exchanger optimization constraints, several optimization strategies are presented. Firstly, the use of metallic foams to improve the heat exchange surface area, then the thermo-physical properties of the heat transfer fluid as part of the formulation of nanofluids or ferrofluids are studied. Finally, the use of ultrasonic waves as an active method for improving the overall performance of heat exchangers is presented. Each of these approaches is approached by means of an experimental procedure to qualify the convective heat transfers and parietal friction induced by the intensification strategy itself, with the ultimate aim of judging the overall energy benefit of this intensification approach. The advantages and disadvantages of these optimization strategies are discussed, and ultrasound appears to have a number of advantages in this quest for energy optimization. In addition to their positive effects on heat transfer, the physical effects of ultrasound on flow are also known to promote micro-mixing, activate some chemical reactions and limit fouling. Taken together, these characteristics suggest positive effects on the performance of heat exchanger-reactors, a concept combining a heat exchanger and a chemical reactor. Several research perspectives, aimed at studying and demonstrating the advantages of this innovative ultrasonic heat exchanger-reactor concept, are presented. The need to use or develop metrological means to refine the phenomenological understanding of ultrasonic/flow interaction is discussed, with a view to developing a modeling methodology for the sizing of ultrasonic heat exchangers-reactors.
Jury :
- Madame Cathy CASTELAIN, Directrice de Recherche, Polytech Nantes - LTEN, rapporteur
- Monsieur Jean Yves HIHN, Professeur, Université de Franche-Comté - UTINAM, rapporteur
- Monsieur Thierry LEMENAND, Maître de conferences HDR, Polytech Angers - LARIS, rapporteur
- Madame Laurie BARTHE, Maître de conferences HDR, Université de Toulouse - LGC, examinateur
- Monsieur Marc MISCEVIC, Maître de conferences HDR, Université de Toulouse - LAPLACE, examinateur
- Monsieur Stéphane BAUP, Professeur, Université Grenoble Alpes - LRP, examinateur