Patent ID: 7918310
Filing Date: 2011-04-05
Classification: B64F,F01D,F05D

Abstract:
1. A noise attenuation device for reducing noise generated by a jet engine under going static testing comprising: (a) a carbon-steel pipe having a predetermined length and a predetermined diameter, wherein said carbon-steel pipe is adapted to receive the jet engine under going static testing and said carbon-steel pipe is aligned axially with the direction of exhaust flow from an exhaust port of said jet engine; (b) said carbon-steel pipe having a front end which is angled outward to provide for adequate air flow of cold air into said carbon-steel pipe from the atmosphere, an interior which receives the cold air from the atmosphere, and a rear end, the exhaust port of said jet engine being positioned at the front end of said carbon-steel pipe, wherein the cold air enters the front end of the carbon-steel pipe at a temperature of approximately 70 degrees Fahrenheit, and has a mass of approximately three times the mass of the hot jet engine exhaust from exhaust port of said jet engine; (c) said carbon-steel tube having an elongated interior for receiving the cold air from the atmosphere and the hot jet engine exhaust from said jet engine and then mixing the hot jet engine exhaust with the cold air forming a jet engine exhaust-cool air mixture; (d) said carbon-steel tube having a rear end portion which includes a plurality of perforated side plates and a rear end which has a blockage cone, wherein said jet engine exhaust-cool air mixture cools from 3800 EF to less than 1200 EF as said jet engine exhaust-cool air mixture travels through the interior of said carbon-steel pipe; (e) a shroud positioned around the exterior of the rear end portion of said carbon-steel tube, said shroud having a flow deflector positioned at the front end of said shroud, wherein an annular region is formed between said perforated side plates and the shroud which surrounds the rear end portion of said carbon-steel pipe; (f) a blockage cone positioned at rear end of the rear end portion of said carbon-steel pipe, wherein said blockage cone assists in forcing a substantial portion of the flow of the jet engine exhaust-cool air mixture through openings within said perforated side walls into said annular region; (g) said annular region slowing average velocity of the jet engine exhaust-cool air mixture and substantially reducing noise produced by said jet engine; and (h) said flow deflector forcing said jet engine exhaust-cool air mixture exiting the front end of said shroud to reverse direction and flow in a rearward direction which is the same direction said jet engine exhaust-cool air mixture flows exiting the rear end of said shroud.