Aviation and the Global Atmosphere

Aviation and the Global Atmosphere
Aviation and the Global Atmosphere
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7.6.4. Current Understanding of Chemical Changes in Turbine and Exhaust Nozzle
Other reports in this collection
Approximately 99.5-99.9% of the molar content of typical commercial engine exhaust consists of N 2 , O 2 , CO 2 , and H 2 O. The species that compose the remaining 0.1-
0.5% exist in trace amounts. This trace exhaust component consists primarily of NO x , CO, unburned HC (including soot), the hydroxy family (HO x , H 2 Ox), the sulfur
oxide family (SO x O), and elemental species such as O. Figure 7-26 provides a general categorization of chemical processes occurring in the turbine and exhaust
nozzle. These processes are discussed in greater detail below.
Table 7-7: Summary of confidence attached to current modeling and measurements of emissions emerging from engines.
Principal Effects of Post-Combustor Reactions
Exhaust Products from Engines and Levels of Confidence Associated with Modeling and Measurements
Primary constituents
(e.g.,H 2 O,CO 2 N 2 ,O 2 )
http://www.ipcc.ch/ipccreports/sres/aviation/105.htm (1 von 4)08.05.2008 02:43:40
Present combustors convert almost all of the kerosene to the products of
complete combustion. Further CO oxidation in the turbine (a few tenths of a
percent or less) slightly increases CO 2 emitted. Prediction capability is good, and
levels are easy to derive from basic engine operating conditions or measurements.