AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
In-situ Measurements of Aircraft Engine Exhaust at Cruise Conditions during the 2013 ACCESS Chase Plane Experiment
RICHARD MOORE, Edward Winstead, Lee Thornhill, Andreas Beyersdorf, Suzanne Crumeyrolle, Luke Ziemba, Bruce Anderson, NASA Langley Research Center
Abstract Number: 260 Working Group: Combustion
Abstract Aircraft engine emissions constitute a negligible fraction of the global black carbon mass, but can have a disproportionate climatic impact because they are emitted high in the troposphere and in remote regions with otherwise low aerosol concentrations. Consequently, these particles are likely to strongly influence cirrus and contrail formation by acting as ice nuclei (IN). However, the ice nucleating properties of aircraft exhaust at relevant atmospheric conditions are not well known, and thus, the overall impact of aviation on cloud formation remains very uncertain.
To address this need, the NASA Alternative Fuel Effects on Contrails and Cruise Emissions (ACCESS) was conducted in February-March, 2013 to examine the aerosol emissions from the NASA DC-8 under a variety of different fuel types, engine power, and altitude/meteorological conditions. Two different fuel types were studied: a traditional JP-8 fuel and a 50:50 blend of JP-8 and a camelina-based hydro-treated renewable jet (HRJ) fuel. Emissions were sampled using a comprehensive suite of gas- and aerosol-phase instrumentation integrated on an HU-25 Falcon jet that was positioned in the DC-8 exhaust plume at approximately 100-500m distance behind the engines. Measurements of aerosol concentration, size distribution, soot mass, and hygroscopicity were carried out along with trace gas measurements of CO2, NO, NO2, O3, and water vapor. Contrail ice crystals were sampled with a DMT Cloud Droplet Probe mounted on the crest of the fuselage, as well as a Cloud Aerosol Spectrometer and a Cloud Imaging Probe on the starboard wing pylon. Emissions indices suggest that the cruise emissions are in line with past ground-based measurements, where similar particle numbers were emitted by burning pure JP-8 and the blended fuel. This indicates that blended fuels do not significantly affect particle emissions, and motivates future measurements of engines burning pure HRJ fuel.