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A New Concept in the Design of Jet Engine Mufflers and Test Cells

Published online by Cambridge University Press:  28 July 2016

E. J. Richards  and
D. J. Evans
E. J. Richards
Affiliation:
Department of Aeronautical Engineering, University of Southampton
D. J. Evans
Affiliation:
Department of Aeronautical Engineering, University of Southampton
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Summary

A new concept is put forward which should help materially in the design of engine test cells and ground mufflers. It is suggested that a relatively small spreader can be added behind a jet nozzle which changes, the shape of the jet from circular to a long annular slot. The frequency rise which may be obtained in this way is used to reduce low frequency noise, possibly at the expense of more easily attenuated high frequency noise. As a modest example, tests are described on one particular version which gives an attenuation in the most important low frequency range of nearly 20 decibels. It is shown that the back pressure on the engine is negligible even with a cooling flow equal to the engine mass flow. Other applications are discussed and tested, while suggestions for full scale installations are made.

Type
Research Article
Information
The Aeronautical Journal , Volume 61 , Issue 561 , September 1957 , pp. 619 - 630
Copyright
Copyright © Royal Aeronautical Society 1957

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References

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