The Boeing Company

William J Hirt

Claude R Stachowiak

Charles A Grotz

Jack H Caldwell

Ira B Rushwald

Henry A Kumasaka

A compressor bleed air passageway includes a duct having an upstream section (48) which terminates in a baffle (44) and a downstream duct section (54) having a forward portion (56) which surrounds the baffle (44). Bleed air flow through openings (58) in the baffle wall (52). This reduces velocity of the bleed air stream at the duct discharge port to a value equal to or less than Mach 1.0. The baffle (44) has virtually no effect on a low-velocity, low-pressure air stream. The downstream duct section (54) may be perforated and surrounded by outer wall (64) to form sound-absorbing chambers (66).

Jet engine noise suppressor

A method of enhancing Coanda flow attachment over a wing and flap surface of an upper surface blowing aircraft comprising the step of directing the jet exhaust flow or stream toward regions wherein the exhaust flow separates from the wing and flap surface so as to create an outward velocity component which prevents ambient air from flowing in and under the exhaust from the sides of the exhaust flow and causing such separation is disclosed. The method comprises the further step of creating vortices also having outward velocity components on the wing and flap surface. The outward velocity components of the vortices further increases the sidewise velocity component on the wing surface. In addition, the rotational velocity components of the vortices scrub the boundary layer air from the flap surface to further promote flow attachment. Apparatus suitable for carrying out the method and comprising a plurality of airfoil shaped vortex generating vanes located between the engine exhaust and the trailing edge of the flap is also disclosed. The vortex generating vanes direct the exhaust stream toward the separation regions and create the outward velocity component vortices.

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Bellevue, WA, United States of America

William J Hirt