BARRELLON-VERNAY Rafaël : Unveiling nucleation mechanism in aircraft engine exhaust and its link with fuel composition
Résumé de thèse : Aviation is currently one of the strongest growing transport sectors, and this trend is predicted to continue. Therefore, the impact of aviation emissions on climate and air quality is a big concern nowadays. The aviation industry has identified the development of biofuels as one of the major tools to tackle its emissions. These emissions are not limited to greenhouse gases like CO2 or water but include as well other gases like nitrogen oxides (NOx) or sulfur oxides (SOx) and volatile and non-volatile particulate matter (vPM and nvPM respectively). nvPM is defined as particles present in the engine exhaust at temperatures higher than 350°C and consists essentially in soot particles produced by the incomplete combustion of the fuel. vPM is formed by nucleation from gaseous precursors in the cooling exhaust gas downstream the combustor, when the concentration of preexisting particles has decreased, favoring homogeneous nucleation versus heterogeneous one (adsorption of gases onto preexisting particles). The molecular mechanism behind this phenomenon is still unknown. The main objective of this PhD thesis is to determine the mechanism behind vPM formation in the engine exhaust and if there is a link with fuel composition. For this, the candidate will use the state-of-the-art Combustion Aerosol Standard (CAST) generator especially designed to work with aeronautic fuels available at ONERA. CAST emission will be characterized at PhLAM laboratory by means of mass spectrometry and Raman spectrometry. To study the formation of vPM in detail, the PhD student will be involved in two measurement campaigns at the atmospheric simulation chamber CESAM (LISA).
Directeur(s) de thèse : C. Focsa - D. Delhaye (ONERA) - I. K. Ortega (ONERA)