CMC AIRFOIL WITH IMPACT RESISTANT LEADING EDGE PLIES
Publication Date: 2015-Apr-02
The IP.com Prior Art Database
An embodiment of the present invention provides airfoils with specifically engineered impact-resistant ceramic matrix composite (CMC) plies. The CMC plies are applied as laminates to the suction sides of rotating airfoils and/or the leading edges of static airfoils. Additionally, the CMC plies may be applied to any part of a turbine engine at risk for domestic object damage (DOD) impact or the wings of aircrafts. The present invention will increase the DOD impact resistance of airfoils, and/or other areas prone to DOD impact and/or other damage.
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CMC AIRFOIL WITH IMPACT RESISTANT LEADING EDGE PLIES BACKGROUND
The subject matter disclosed herein relates generally to turbine engines, and more specifically to airfoils within a turbine engine (hereinafter "airfoils or guide vanes or turbine airfoils, fan blades or blades").
Airfoils generally refer to the shape of an aircraft's wings that aids in facilitating takeoff, gliding through the air, and landing. However, airfoils can also be found in fans, propellers, compressors and turbine engines. Typically formed from strong and durable metal alloys, such as ceramic matrix composites (CMC), polymer composites, and metal alloys including CMC composites and polymer composites, airfoils are engineered to improve the durability and strength of a turbine engine and resist domestic object damage (DOD) impact, which usually occurs under operating conditions.
Referring to Figure 1, airfoils generally comprise a leading edge, a trailing edge, a pressure side, a suction side, a chord line, and a camber line. The leading edge refers to the area of the airfoil proximal to the incoming flow stream, while the suction side refers to the upper surface of rotating airfoils that is generally associated with higher velocity and lower static pressure. Due to the harsh environments within which turbine airfoils operate, DOD impact is inevitable. This leads to the erosion of the material or materials that make up the airfoils, particularly at the leading edges and suction sides.
A technique that is often employed to prevent this erosion is the use of thin V-shaped metallic strips, which are wrapped around the leading edge and cover a substantial portion of the pressure and suction sides of turbine airfoils. This technique, however, presents several disadvantages because the strips can detach/delaminate in whole or in part during operation,
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which may lead to airfoil and engine component damage, while increasing maintenance costs associated with repairing/replacing strips and damaged engine components. Accordingly, there is a need for an airfoil design that overcomes these disadvantages.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 illustrates a cross-section view of an exemplary airfoil.
Figure 2 illustrates a three-dimensional view of an airfoil, according to an embodiment of the present invention.
Figure 3 illustrates a turbine engine with impact resistant airfoils, according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
To overcome the disadvantages outlined above, the present invention uses engineered impact resistant plies on airfoils, and more specifically CMC plies on the leading edges and/or the suction sides of airfoils.
Referring now to the drawings in detail, there is shown in Figure 2 an airfoil 20 in accordance with an embodiment of the present invention. The airfoil 20 comprises a leading edge 22, a trailing edge 24, a pressure side 26, a suction side 28, a chord line 25, and a camber line...