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US 10,094,332 B2Granted
Core cowl for a turbofan engine
AssigneeThe Boeing Company
InventorsDavid F. Cerra, Paul Robert Tretow, Robert H. Willie, Abhishek Sahay
Life of this patent
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Abstract
A core cowl for a turbofan engine may include a plurality of valleys formed in an outer surface of the core cowl. Each valley may include a convex portion upstream of a concave portion, and may be configured to disrupt a shock cell exiting a fan nozzle of the turbofan engine. Associated methods for reducing turbofan engine noise are also described.
Claims15
A device for a turbofan jet engine comprising:
- a core cowl having a conical surface extending beyond a fan nozzle exit wherein the conical surface has a first diameter at a forward end proximate a turbine and a second diameter aft of the fan nozzle exit, wherein the first diameter is larger than the second diameter;
- and
- a plurality of elongate depressions formed in the conical surface, such that adjacent elongate depressions are separated by unmodified portions of the conical surface, each elongate depression extending generally from a proximal end portion of the conical surface to a distal end portion of the conical surface;
- wherein each elongate depression comprises an expansion region shaped to expand an impinging shock cell and a compression region shaped to compress the impinging shock cell, the expansion region being upstream of the compression region;
- and
- wherein the expansion region is defined by a first surface angled from the conical surface toward a central axis of the core cowl and the compression region is defined by a second surface angled toward the conical surface;
- and
- wherein the expansion region is generally convex and the compression region is generally concave.
5 more elements
A turbofan nozzle comprising
- a fan sleeve at least partially surrounding a core cowl, an annular fan nozzle being generally defined between the fan sleeve and the core cowl;
- wherein the core cowl includes a conical surface having a first diameter at a forward end proximate a turbine and a second diameter aft of an exit of the fan nozzle, wherein the first diameter is larger than the second diameter, and a plurality of valleys formed in the conical surface such that adjacent valleys are separated by unmodified portions of the conical surface, each valley including an expansion region disposed upstream of a compression region, such that the core cowl is configured to reduce a shock strength of a shock cell pattern flowing over the core cowl;
- and
- wherein the expansion region is defined by a first surface angled from the conical surface toward a central axis of the core cowl and the compression region is defined by a second surface angled toward the conical surface;
- and
- wherein the expansion region includes a convex surface and the compression region includes a concave surface.
3 more elements
A method for reducing noise caused by a turbofan engine, the method comprising:
- disrupting a shock cell exiting an annular fan nozzle by
- expanding a first portion of the shock cell by impinging the first portion upon a first region of a core cowl having a conical surface with a first diameter at a forward end proximate a turbine, and a second diameter aft of an exit of the fan nozzle, wherein the first diameter is larger than the second diameter, the first region including a convex surface shaped to expand the first portion of the shock cell;
- compressing a second portion of the shock cell by impinging the second portion upon a second region of the core cowl disposed downstream of the convex surface, the second region including a concave surface shaped to compress the second portion of the shock cell;
- and
- passing a third portion of the shock cell over an unmodified portion of the conical surface laterally adjacent to the convex surface and the concave surface;
- and
- wherein the convex surface is angled from the conical surface toward a central axis of the core cowl and the concave surface is angled toward the conical surface.
4 more elements
Dependencies are inferred from the claim text.