The Boeing Company

Ronald L Balzer

Michael L Sangwin

Daniel T Jensen

Leonard J Hebert

Michael W Su

Jerry Piro

Jeff P Lewis

Robert E Moody

Disclosed is a means for reducing jet engine exhaust noise wherein mixing is enhanced between adjacent exhaust flows and between exhaust flow and free-stream flow. Also disclosed is a means for improving the thrust of jet engines and for reducing the noise and drag of aircraft. The device is a segmented, triangular or trapezoidal shaped, curved extension to a nozzle's sleeve or surface trailing edge that results in a serrated trailing edge. The extensions enhance the natural free mixing of the adjacent flows and therefore reduce the acoustic energy associated with the velocity differences between the streams in which they are imbedded. The novel structure forces adjacent flows to penetrate into one another to a greater depth than that achieved with free mixing and results in a more uniform flow in a shorter stream wise distance. As a result of the enhanced mixing, drag on flow surfaces that are downstream of the devices and are scrubbed by the flows adjacent to the devices can be reduced.

Segmented mixing device for jet engines and aircraft

Disclosed is a segmented mixing device for reducing jet engine exhaust noise wherein mixing is enhanced between adjacent exhaust flows and between exhaust flow and free-stream flow. The device does so with a very small degradation in aircraft performance. The device is a segmented, triangular or trapezoidal shaped, curved extension to a nozzle's sleeve that results in a serrated trailing edge. The nozzle extensions enhance the natural free mixing of the jet's exhaust flows and therefore reduce the acoustic energy associated with the velocity differences between the streams in which they are imbedded. The novel structure forces adjacent flows to penetrate into one another to a greater depth than that achievable with free mixing and results in a more uniform flow in a shorter stream wise distance while limiting high frequency noise through utilization of root radii in the order of 15 to 20% of the segment's width at the intersection of a parent nozzle.

Segmented mixing device having chevrons for exhaust noise reduction in jet engines

Disclosed is a means for reducing jet engine exhaust noise wherein mixing is enhanced between adjacent exhaust flows and between exhaust flow and free-stream flow. The device does so with a very small degradation in aircraft performance. The device is a segmented, triangular or trapezoidal shaped, curved extension to a nozzle's sleeve that results in a serrated trailing edge. The nozzle extensions enhance the natural free mixing of the jet's exhaust flows and therefore reduce the acoustic energy associated with the velocity differences between the streams in which they are imbedded. The novel structure forces adjacent flows to penetrate into one another to a greater depth than that achievable with free mixing and results in a more uniform flow in a shorter stream wise distance.

A fencing assembly (66) for prohibiting circulation of primary and/or fan airflows (52), (54) into a bounded low pressure region of a jet engine installation. The fencing assembly includes one or more flow control fences. In an exemplary application, the fencing assembly includes a number of fences positioned around the sides of a batcave (48) bounded low pressure region that is located between a primary exhaust nozzle (20) and strut fairings (30). The fencing assembly includes five fences, each fence being connected to either the primary exhaust nozzle or the strut fairings. The five fences include single fences (70), (72) positioned along each lateral side of the batcave; two rear fences (74), (74') positioned circumferentially about rear regions of the batcave; and an arcuate fence (76) positioned near the two rear fences to form a half circle. The fences include a foot portion (78) and an upright portion (80).

Engine flow control device

An improved pressure relief system for a turbine engine (10). The pressure relief system includes a pressure relief door (12) attached to the engine shroud (16) at its forward edge. The aft edge of the door (12) is free to pivot onward in the occurrence of a bleed duct failure. The door (12) is mounted within a cutout (26) in the engine shroud (16). The cutout (26) is sized so that the width of the forward edge of the cutout is greater than the width of the aft edge of the cutout. Opposing walls (42) on either side of the door (12) extend from the forward edge of the door at least partially to the aft edge of the door. The walls (42) extend inward approximately normal to the surface of the door (12). The walls (42) prevent hot engine gases (36) from flowing out of the sides of the cutout. Preventing hot engine gases (36) from flowing out the sides of the cutout helps to alter the air flow around the door (12) to obtain greater mixing of cool bypass air with the hot engine gases. The resulting cooler air flow decreases engine shroud (16) temperatures aft of the pressure relief door (12). The decreased temperatures on the engine shroud (16) during a bleed duct failure help to eliminate the structural requirements for high temperature materials or insulating blankets.

Flow control apparatus for gas turbine engine installation pressure

An improved pressure relief system for a turbine engine (10). The pressure relief system includes a pressure relief door (12) attached to the engine shroud (16) at its forward edge. The aft edge of the door (12) is free to pivot outward in the occurrence of a bleed duct failure. The door (12) is mounted within a cutout (26) in the engine shroud (16). The cutout (26) is sized so that the width of the forward edge of the cutout is greater than the width of the aft edge of the cutout. Opposing walls (42) on either side of the door (12) extend from the forward edge of the door at least partially to the aft edge of the door. The walls (42) extend inward approximately normal to the surface of the door (12). The walls (42) prevent hot engine gases (36) from flowing out of the sides of the cutout. Preventing hot engine gases (36) from flowing out the sides of the cutout helps to alter the air flow around the door (12) to obtain greater mixing of cool bypass air with the hot engine gases. The resulting cooler air flow decreases engine shroud (16) temperatures aft of the pressure relief door (12). The decreased temperatures on the engine shroud (16) during a bleed duct failure help to eliminate the structural requirements for high temperature materials or insulating blankets.

Gas turbine engine power plants of the ducted fan type. During reversed thrust operation of the power plant, air is induced into the bypass duct through two inlets in one type of power plant is concerned. One of these, a secondary inlet, is located between a stationary front section of the bypass duct and a translated rear section. A gas or fluid such as air is injected at high velocity into the bypass duct to turn air induced through the secondary inlet into paths paralleling the longitudinal centerline of the duct or to accomplish this goal and also promote the attachment of induced air to the inner surface of the bypass duct. In both cases, the efficiency of the power plant in the reversed thrust mode of operation is increased. A second type of power plant of interest does not have a translatable rear section. Nevertheless, the operating efficiency of that type of engine can be promoted in the reversed thrust mode of operation by so injecting gas or fluid into the bypass duct as to promote the attachment of air moved through that duct by the power plant fan to its inner surface.

Growing community of inventors

Bothell, WA, United States of America

Ronald L Balzer