Excess noise from gas turbine exhausts
- Creators
- Cumpsty, N. A.
Abstract
There is evidence to show that the exhaust noise from gas turbines contains components which exceed the jet mixing noise at low jet velocities. This paper describes a theory developed to calculate the acoustic power produced by temperature fluctuations from the combustor entering the turbine. Using the turbine Mach numbers and flow directions at blade mid-height, and taking a typical value for the fluctuation in temperature, it has been possible to predict the acoustic power due to this mechanism for three different engines. In all three cases the agreement with measurements of acoustic power at low jet velocities is very good. Using a measured spectrum of the temperature fluctuation the prediction of the acoustic power spectrum agrees quite well with that measured.
Additional Information
© 1974. This work has been heavily dependent on the cooperation of the aeronautics industry. The author wishes to thank Rolls Royce (1971) Ltd. for aerodynamic and noise data for the Spey 512 and Olympus 593, Pratt and Whitney Aircraft for aerodynamic data on the JT8D, and the Boeing Commercial Airplane Company for noise measurements from the JT8D. He would in particular like to express his gratitude to R. R. Dils of Pratt and Whitney Aircraft whose guidance on combustion chamber behavior was invaluable.Attached Files
Submitted - 258_Cumpsty_NA.pdf
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Additional details
- Eprint ID
- 22032
- Resolver ID
- CaltechAUTHORS:20110207-081618338
- Created
-
2011-02-07Created from EPrint's datestamp field
- Updated
-
2019-10-03Created from EPrint's last_modified field
- Caltech groups
- Guggenheim Jet Propulsion Center
- Other Numbering System Name
- Guggenheim Jet Propulsion Center