AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
On Generating Sub-100-nm Soot Particles with the Argonaut Miniature Inverted Soot Generator
JOEL CORBIN, Senaratne Amrith, Jason S. Olfert, Gregory Smallwood, Stephanie Gagne, Fengshan Liu, Prem Lobo, National Research Council Canada
Abstract Number: 268 Working Group: Combustion
Abstract The graphitic, strongly light-absorbing carbonaceous particles generated by incomplete combustion (soot) play a major role in air pollution toxicity and the radiative forcing of the climate. As these effects are dependent on particle size and composition, it is essential that laboratory studies are performed on soot which accurately represents real-world sources.
The Argonaut miniature inverted soot generator (MISG) employs a simple design to produce soot which is similar to real-world soot in terms of size and degree of graphitization, with a mode mobility diameter of ~150 nm achieved when using ethylene (Kazemimanesh et al., 2018) or propane (Moallemi et al., 2019) in its two-flow, air–fuel diffusion flame. These particles are useful surrogates of the soot produced by internal combustion engines or biomass combustion. However, they are substantially larger than the very small (~50 nm) and highly graphitic particles typically observed in the exhaust of aircraft engines (Vander Wal et al., 2014; Liati et al., 2014).
In this work, we therefore explore the ability of the MISG to produce aircraft engine-like soot, that is, small (<100 nm) and highly-graphitic soot. We employed a range of gas–fuel mixtures, including propane, acetylene, and oxygen-enriched air. We measured particle size using a scanning mobility particle sizer (SMPS). We evaluated the degree of graphitization by real-time measurements of the mass absorption cross-section (MAC) of our samples using the CPMA-Electrometer Reference Mass System (CERMS) and, for certain conditions, verified our interpretations using filter-based measurements of its elemental carbon (EC) content using thermal optical analysis. We found that particle size is relatively insensitive to the fuel mixture, yet certain fuel mixtures were identified which generated size distributions of approximately 100 nm mobility diameter.