Measurements and Predictions of Flyover and Static Noise of a TF30 Afterburning Turbofan Engine. Technical Report NASA Technical Paper TP-1372, Research Engineering, NASA Dryden Flight Research Center

Burcham Jr., Frank W. and Lasagna, Paul L. and Oas, Stanley C. (1978) Measurements and Predictions of Flyover and Static Noise of a TF30 Afterburning Turbofan Engine. Technical Report NASA Technical Paper TP-1372, Research Engineering, NASA Dryden Flight Research Center.

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Abstract

The noise of the TF30 afterburning turbofan engine in an F-111 airplane was determined from static (ground) and flyover tests. A survey was made to measure the exhaust temperature and velocity profiles for a range of power settings. Comparisons were made between predicted and measured jet mixing, internal, and shock noise. It was found that the noise produced at static conditions was dominated by jet mixing noise, and was adequately predicted by current methods. The noise produced during flyovers exhibited large contributions from internally generated noise in the forward arc. For flyovers with the engine at nonafterburning power, the internal noise, shock noise, and jet mixing noise were accurately predicted. During flyovers with afterburning power settings, however, additional internal noise believed to be due to the afterburning process was evident; its level was as much as 8 decibels above the nonafterburning internal noise. No prediction is available for afterburning internal noise. Designs of future afterburning or duct-burning engines should take into consideration the effects of internal noise, which may not be evident from static testing. Power settings that produced exhausts with inverted velocity profiles appeared to be slightly less noisy than power settings of equal thrust that produced uniform exhaust velocity profiles both in flight and in static testing.

EPrint Type:	Other
Keywords:	Afterburning engines, Exhaust noise, F-111 aircraft, Flyover noise, Jet noise, Noise prediction
Subjects:	(01 - 09) Aeronautics: (07) Aircraft Propulsion And Power Aircraft/Project: F-111
ID Code:	1120
Deposited On:	21 November 2006
Additional Information:	94 pages.