AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Optical Properties of Black Carbon Particles in Aircraft Engine Exhaust: Engine Type, Operating Conditions, and Fuel Effects
MIRIAM ELSER, Benjamin Brem, Lukas Durdina, David Schönenberger, Jing Wang, Empa, Switzerland
Abstract Number: 169 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract Black carbon (BC) from aircraft engine exhaust is a unique contributor to the particulate mass in the upper troposphere and has significant impacts on radiative forcing and climate. A detailed characterization of the optical properties of BC is essential to estimate its climate effects. Measurements were performed at the engine testing facility of SR Technics at Zurich Airport (Switzerland). Five widely used types of commercial turbofan engines were tested over a range of operating conditions from idle to take-off thrust using regular Jet A-1 fuel and various blends with HEFA (Hydro-processed Esters and Fatty Acids) fuel. The engine exhaust was sampled at the engine exit by a single-orifice probe. The non-volatile particulate matter (nvPM) mass and number concentrations as well as gaseous pollutants were measured according to the regulatory standards. To study the wavelength dependence of the optical properties of the BC emissions, we deployed a cavity Attenuated Phase Shift-based single scattering albedo monitor (CAPS PMssa, λ = 532 nm) and a Photoacoustic Extinctiometer (PAX, λ = 870 nm). Filter samples were taken during periods with stable operating conditions for the quantification of elemental and organic carbon (EC/OC) using thermal-optical analysis. For all engine types, the extinction, absorption, and scattering coefficients show similar increasing trends for increasing thrust level (and nvPM mass). The use of HEFA fuel blends reduced substantially the nvPM mass and optical coefficients, especially at low thrust levels. A detailed characterization of the major optical properties (including single scattering albedo, absorption and extinction Angstrom exponents, and mass absorption cross sections) of aircraft BC emissions and their dependence on engine type, operating conditions, and fuel type will be presented at the conference.