The Role of Black Carbon Emitted from Aircraft Engines as a Condensational Sink of Oil and Sulfur Particles
BENJAMIN A. NAULT, Andrew Freedman, Edward Fortner, Bruce Anderson, Steven Baughcum, Matthew Brown, Josh DiGangi, Francesca Gallo, 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: 339
Working Group: Combustion
Abstract
Black carbon (BC) emissions from aircraft engines have been studied due to its role as ice nuclei (IN) and its interactions with radiation. With advancements in aircraft engine technology, and the usage of sustainable aviation fuel (SAF), BC emissions have greatly reduced. An understanding of the role of other emissions from aircraft engines is needed as they may have different impacts towards IN potential. The emissions can include sulfur and oil, and depending on how they are emitted, the role of BC as a condensational sink (CS) may impact the observed emission ratios for these two particle classes. Here, we use observations collected from ground-based observations of aircraft emissions from the Boeing ecoDemonstrator project (2021 – 2023). During these tests, the emissions from a various combustor design in turbofan using different fuels were sampled on the NASA Langley Mobile Laboratory with various instruments to quantify the particle emissions, including an SP-AMS, a CAPS PMssa, and a heated SMPS for size distributions of non-volatile particles. We found that burning of Jet-A fuel led to a CS from BC of ~3×10-5 s-1 at the highest thrusts (>70%) on the staged lean-burn combustor; significantly less than observed on the “conventional” combustor. This led to a decrease in the normalized particle sulfate emission factor of 4 between the conventional and staged combustor engine approximately similar thrust values and nominally similar sulfur content. Burning the SAF fuel in the staged combustor decreased the CS by almost an order of magnitude to ~4×10-6 s-1. This led to a decrease in particulate oil and sulfate emissions at the highest thrusts (>70%) by ~20% (sulfate) and ~10% to >100% (oil) than compared to burning Jet-A with the same engine. The impact of reduced CS for IN is being further evaluated.