Jet engine noise attenuator

Abstract

Abstract 831,776. Exhaust-silencers. LEMMERMAN Inc., C. W. March 21, 1958 [July 29, 1957], No. 9078/58. Class 7(2) A portable or fixed ground silencer for jet engines comprises a sheet metal casing 10, Fig. 2, with an upturned exit 14, a sound-absorbing lining 18 constructed as in U.S.A. Specification 2,674,336, and a diffuser 23 supported by vanes 22 and having a gas entry 26 for connection to or reception of a jet engine tail pipe and gas exit perforations 32 increasing in size and spacing towards its downstream end and having a total area at least equal to that of the tail pipe. The upstream perforations 32 are small enough to prevent passage therethrough of cooling air drawn in between the members 10 and 23. The diffuser 23 may be wholly conical and of wire mesh and supported at its front and rear only, the lining 18 being optionally omitted or disposed only in the area of the diffuser. Figs. 5 and 6 show a diffuser formed of axially spaced notched rings 239 with flanges 241 interconnected by ribs 243; such a diffuser may be used with a wire mesh diffuser formed as above covering it. In Fig. 8 a diffuser is formed by a perforated cylinder 424 and rings 447 supported by ribs 448. A core 449 and an annular air guide 446 are provided, together with supporting vanes 449<SP>1</SP>, 422<SP>1</SP> and 422.

Inventors

No inventors recorded.

Bibliographic Details