Gaseous and Particulate Emissions Results of the NASA Alternative Aviation Fuel Experiment (AAFEX)

Abstract

The Aircraft Alternative Fuels Emissions experiment (AAFEX) was conducted at National Aeronautic and Space Administration (NASA) Dryden Flight Research Center (DFRC) Aircraft Operations Facility (DAOF) in Palmdale, California, during January and February 2009. The purpose was to systematically investigate the effect of alternative fuels on both gas-phase and particle emissions from a CFM56-2C1 engine on NASA’s DC-8 aircraft parked on the ground as functions of engine power, fuel composition, and exhaust plume age. Emissions parameters were measured at 6 engine power settings, ranging from idle to maximum thrust, in samples collected at 1, 30, and 145 meters (m) downstream of the exhaust plane as the aircraft burned three pure fuels and two fuel blends. The fuels included JP-8, two fuels produced using the Fischer-Tropsch process and 50/50 blends by volume of the F-T fuels with JP-8. The 1 m sampling rakes contained multiple gas and particle inlet probes and could also be traversed in order to measure the spatial variation of emissions across the engine exhaust plane. The #2 inboard engine on the left side always burned JP-8 while the #3 inboard right side engine was fueled with the various fuels and fuel blends. In addition, emissions from the Auxiliary Power Unit (APU) were also evaluated with both JP-8 and one pure F-T fuel. Both gaseous and particulate emissions are presented. Results show that the synthetic fuels reduced pollutant emissions while having relatively little effect on engine operation or performance.

Alternate-Fueled Combustor-Sector Performance—Part A: Combustor Performance and Part B: Combustor Emissions

“…Post-AAFEX 2010 Workshop data [9] also show similar qualitative emissions trends with results herein, yet elude quantitative comparisons for lack of scales on many of the AAFEX reported data.…”

Composition and Sources of the Organic Particle Emissions from Aircraft Engines

“…All data are from the APEX-3, AAFEX-1, and AAFEX-2 field studies (Bulzan et al 2010). Table 1 lists the relevant experimental details.…”

“…Timko et al (2010a) provide more detail on the APEX-3 aircraft engines and fuels; their trace gas (Timko et al 2010a;Beyersdorf et al 2012) and PM emissions (Timko et al 2010b) performance have been reported previously. Bulzan et al (2010) and Wey et al (2007) provide more detail on the engine emissions performance of the DC-8 aircraft and its CFM56-2C1 engines used during the AAFEX campaigns. Both APEX-3 and AAFEX used an experimental protocol that has been described previously ).…”

“…Unlike the lubrication oils, combustion of FT fuels and blended fuels may lead to a true reduction in the emissions of combustion related organic PM as combustion of these reduced aromatic fuels reduces emissions of soot and many VOCs (Bulzan et al 2010). Using a sampling protocol that provides time for particles initially smaller than 80 nm to grow to sizes that are detected efficiently by the AMS, Timko et al (2013) quantified the reductions in organic PM emission observed with combustion of low aromatic fuels.…”

“…Motivated by these environmental concerns, researchers have performed studies to advance the current state of knowledge of gas turbine engine NO X Wormhoudt et al 2007;Wood et al 2008;Timko et al 2010a; Lee et al 2011;Santoni et al 2011), volatile organic compounds (Spicer et al 1994;Herndon et al 2006Herndon et al , 2009Knighton et al 2007;Yelvington et al 2007;Timko et al 2010c;Beyersdorf et al 2012), and PM emissions (Herndon et al 2005bLobo et al 2007Lobo et al , 2011Hagen et al 2009;Onasch et al 2009;Bulzan et al 2010;Timko et al 2010b). Partly because the knowledge base was limited and partly due to the potential impacts, particular emphasis has been placed on characterizing turbine engine PM emissions.…”