Characterization of Aviation Soot Emissions With a High-Pressure Gas Turbine Combustor Rig

Characterization of particulate matter (PM) emissions from commercial and military aircraft engines is a costly procedure, usually influenced by a number of uncontrollable technical issues such as ambient conditions. In this study we demonstrated that a research sector rig representing an aircraft engine combustor can be used to evaluate PM emissions, such as carbonaceous soot, in a well-controlled manner. PM emissions in terms of mass and number, as well as particle size distribution and optical properties, were characterized and quantified with a variety of state-of-the-art measurement instruments. Compared to previously published measurements on advanced commercial aircraft engines (CFM56-7B22), the measured emission index of black carbon soot was 58±3 mg/kg-fuel at simulated higher power conditions, consistent within 25% of field measurements. Measurements of number emission index were within a factor of 2 and geometric mean diameter was between 25 and 35nm again similar to field measurements on engines. Based on the measurements on particle mass and size, the mass mobility exponent of the soot particles had a lower limit of 2.4 indicating near-sphericity and an average density near 1 g/cm³.