Supersonic Engine

Supersonic Engine Technology and Work by the

Committee on Aviation Environmental Protection (CAEP)

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• 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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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• The current supersonic standard seems to be outdated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...