Experiment to Characterize Aircraft Volatile Aerosol and Trace-Species Emissions

During Excavate in January 2002, LARGE scientists at NASA Langley Research Center measured the production of aerosols and aerosol precursors behind the RB-211 engines of the NASA 757 and the J85-GE engines of the NASA T-38A as a function of engine power, fuel-sulfur content and plume age (during ground based operations).

The team studied aerosol number densities and size distributions, CO2, SO2, SO3, H2SO4, HONO, HNO3, NMHC and halocarbons were measured along with supporting experimental parameters (exhaust gas velocity, engine power, fan speed, combustor temperatures, and fuel-flow rates. Using aerosol and gas probes, data was collected behind the NASA T-38A and B-757 at distances between 1 and 35 m. Fuels with differing sulfur contents were used to evaluate the impact of fuel sulfur on aerosol particle densities in the exhaust plume. Aircraft power was adjusted from idle to near takeoff conditions.

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Sampling probes placed behind four engines studied during EXCAVATE.

 
Emissions of CO and hydrocarbons were reduced as power increased.

Related Publications:

Anderson et al, Atmospheric Environment '06; http://www.sciencedirect.com/science/article/pii/S1352231005009295; turbine engines emit considerable amounts of light hydrocarbon species at idle, but significantly lesser amounts at higher engine powers.

Anderson et al, NASA/TM-2005-213783 ‘05. General Overview