Continued Role of Oil and Sulfur in Ground-based Aircraft Engine Particle Emissions during the Boeing ecoDemonstrator 2022 Measurements

BENJAMIN A. NAULT, Andrew Freedman, Edward Fortner, Bruce Anderson, Steven Baughcum, Matthew Brown, Josh DiGangi, Francisco Guzman, Jennifer Klettlinger, Kevin Sanchez, Michael Shook, Gregory Smallwood, Elizabeth Wiggins, Edward Winstead, Luke Ziemba, Richard Miake-Lye, Richard Moore, Aerodyne Research, Inc.

     Abstract Number: 115
     Working Group: Combustion

Abstract
Advancements in technology and fuel sources have led to reductions in the non-volatile and volatile particle emissions from aircraft gas turbine engines. To understand these changes, particle and trace gas emissions were sampled on the ground at 56 m behind two different engines during the 2022 Boeing ecoDemonstrator project located at Boeing Everett Airfield in Everett, WA, USA. Four different fuels were investigated, including 100% sustainable aviation fuel (SAF), petroleum-based Jet A fuel, petroleum-based Jet A low sulfur fuel, and a SAF blend. Chemical composition of the non-volatile and volatile particles was measured by an Aerodyne Aerosol Mass Spectrometer (AMS); black carbon (BC) was measured using an Aerodyne CAPSSSA monitor operating at 630 nm.

The measurements showed two trends for volatile organic aerosol (OA). When oil was intentionally removed from the emissions, the volatile OA contributed minimal mass and minimal fractional contribution to the total aerosol carbon (OA + BC) as aircraft thrust increased. However, when oil was not removed from the emissions, volatile OA increased with engine thrust. The increase in OA mass concentration led to increases in the OA contribution to total aerosol carbon.

Further, sulfur aerosol was consistently above the background sulfur mass concentration. This indicated that even for fuels with low sulfur, there was still enough sulfur to contribute to volatile aerosol. However, as sulfur contribution has decreased, the nitrate contribution appears to be increasing. Impacts on sulfur overall decreases will be discussed.

The combination of sulfur, nitrate, and oil aerosol will have impacts on the physicochemical properties of aerosol both at ground level and at altitude, which is still under investigation.

Finally, multiple measurements of BC were conducted during the 2022 Boeing ecoDemonstrator project. A comparison of these BC measurements and the resulting BC emissions data will be discussed.