Measuring Non-Volatile Particle Properties in the Exhaust of an Aircraft Engine

The steady growth of air traffic and its foreseen expansion during future years have raised concerns about its potential impact on climate and ground-level air quality. So far, the smoke number has been used to evaluate the non-volatile particulate matter amount emitted by aircraft engines, but it is a poor proxy for modern engine emissions. Therefore, new sampling and measurement techniques have recently been tested on aircraft engine emissions, especially as a new ICAO particle emission standard is currently being developed. Number and mass of emitted particles are generally used, but are not sufficient to fully characterize soot emissions and further address atmospheric impact issues. Chemical composition is crucial to evaluate their atmospheric reactivity. This paper presents a complete set of techniques that have been used to characterize soot emissions from an aircraft engine in a comprehensive manner. It reports results from a campaign on a PowerJet SaM146 engine, performed within the framework of the MERMOSE (Mesure et Etude de la Réactivité des émissions de MOteurS aEronautiques) project. It emphasizes the influence of the engine regime, ranging from 30% to 100% of the takeoff thrust, on the various particle properties investigated, including the size, number, morphology and chemical composition.