Environmental Engineering Reference
In-Depth Information
12.0
12.0
changed
characteristics
with deterioration
8.0
8.0
deterioration
optimal
characteristics
normal
function
4.0
4.0
0
0
0
200
400
600
800
1 000 1 200
[°C]
0
200
400
600
800
1 000 1 200
exhaust gas temperature [°C]
120
deterioration
80
normal
function
40
0
0
200 400 600 800 1 000 1 200
exhaust gas temperature [°C]
Fig. 5.3
Change of emission index by wear
5.4 Emissions in Aviation
In contrast to reciprocating engines in vehicles, airplane jet engines show very
gentle concentration distributions without high peaks, except during takeoff and
landing phases. The mass flow is mainly dependent on the load and altitude, which
correlates to the speed. The concentration of exhaust gases is usually very low,
because of high dilution from the secondary air flow produces a low polluted
mixture in the exhaust pipe of the engine. However, the total mass flow of pol-
lutants and CO
2
is basically high.
Measurement of combustion procedures does not belong to the typical monitoring
of jet engine technology yet, although deviations in engine operation clearly lead to
higher fuel consumption and higher exhaust gas emissions. Recent technology oper-
ates with analyzes for temperature, pressure, and number of revolutions. Consider-
ations of wear and tear are based on Emission Index technology; see Fig.
5.3
[
24
].
Emission Index technology surveys the emission of the engine on the test bench
during the certification procedure and uses statistical results of short- and long-
term observation of an engine's operation.
To estimate wear and tear of the engine, exhaust gas emissions are measured at
test benches and given the standardized LTO cycle represented by an engine power
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