The Boeing Company

Thomas A Gally

Michael W Su

Steve D Podleski

Sean A Newsum

A turbo fan engine nacelle houses an engine which forces engine exhaust through a primary nozzle and a fan nozzle positioned along a common central axis. The primary nozzle is bordered interiorly by a primary nozzle plug and bordered exteriorly by a primary nozzle sleeve. The fan nozzle is bordered interiorly by a core cowl and bordered exteriorly by a fan nozzle sleeve. The primary nozzle plug includes a generally cone shaped outer surface which is concave when viewed in side elevation. The concave outer surface has a radius of curvature (R,). The core cowl has a distal end which is radially spaced from the outer surface of the primary plug by a distance (&Dgr;H) in a direction perpendicular to the central axis. The primary nozzle plug and core cowl define a ratio R,/&Dgr;H between approximately 14 and 18. The distal end of the core cowl has a core cowl radius R,with respect to the central axis. A discharge end of the fan nozzle sleeve has a fan nozzle sleeve radius R,, wherein a ratio R,/R,is between approximately 0.4 and 0.6. The outer surface of the primary plug forms a primary plug angle &phgr;,between approximately 13&deg; and 19&deg; with respect to the central axis at the primary nozzle exit. The proper scaling of these key dimensions thereby defines a primary nozzle which reduces the shock associated noise of the turbo fan engine.

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Seattle, WA, United States of America

Thomas A Gally