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Category: Science and Technology
Date Submitted: 07/13/2010 07:02 AM
Supersonic Engine Technology and Work by the
Committee on Aviation Environmental Protection (CAEP)
[pic]
• Past alleviation seems to be based on Concorde emissions
performance
– Little reason for alleviation today, but the smaller BPR of supersonics does not
help within the CAEP LTO (Landing and Take-Off) emissions cycle.
– The supersonic LTO cycle times have small differences, and one question the
group has struggled with is will supersonics operate similar to subsonics below
3,000 feet.
Supersonic Engine Emissions CAEP Work
Figure 4. Comparison of NOx Emissions Regulations for Subsonic and
Supersonic Aircraft
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20
40[pic]
Review of LTO Standards for Supersonic Engines
• CAEP Working Group 3 has reviewed the history of the supersonic LTO
Standard
• Development dates back to the 1970ies
• Draft Standard was based on data from Concorde engine
• There was no commercial development of SST aircraft when the Standard was
introduced
• No changes have been made since the first introduction
• The current supersonic standard seems to be outdated
First conclusions:-
• Current supersonic standard should not be applied for new engine
projects
• Any alleviation compared to the current subsonic Standard would
require detailed technical investigation
Taken from chair of task
groups paper presented to
CAEP Working Group 3.
What about cruise NOx performance?
[pic]Combustor Conditions for Subsonics and Supersonic Engines
This chart illustrates that the combustion design is heavily
dictated by cruise conditions. This also makes NOx at cruise
more difficult and could drive combustion technology. Quiet Supersonic Transport Propulsion
Conflicting Requirements
• High thermal efficiency at supersonic cruise requires high
cycle temperatures
– High T30 and TET for the duration of cruise will
produce low hot component life
– NOx generation is related directly to T30 (in
particular) and will be high at cruise
• Low takeoff (jet) noise requires...