Aviation and the Global Atmosphere

Aviation and the Global Atmosphere
Figure 7-16: Schematic of soot production process.
Future combustors are likely to face even more challenging requirements as manufacturers respond to the continuing need to increase fuel efficiency. As explained in
Section 7.4.1, higher cycle pressure ratios lead to improved engine fuel efficiency. However, the compressor delivery/combustor inlet air temperatures rise, reducing
the cooling capacity of the air. A greater proportion of total airflow is then needed to cool the hottest parts (liners, blades, etc.). In turn, this requirement reduces airflow
available for primary combustion and dilution, making it more difficult to control turbine inlet temperature profiles and emission levels. This cycle of primary and
secondary problems, which stem from increases in engine pressure ratios, can be broken only by continuously improving the effectiveness of cooling techniques and
devices and/or the use of new and improved materials.
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