Integral CMC Gas Turbine Blade Platform Sealing
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Solution Overview
Problem
Current composite gas turbine engine blades made of low ductility ceramic matrix composites face challenges in sealing the gap between the airfoil and platform, leading to uncontrolled leakage and reduced engine efficiency due to their mechanical properties and manufacturing limitations.
Innovation Solution
A composite blading member with an integral airfoil and base, both made of stacked layers of fibrous material, where the platform is also composed of the same material and interfused with the airfoil and base, eliminating the need for a separate metallic platform and addressing sealing issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a separate metallic platform is used with CMC airfoil and base, then the blade can be manufactured with CMC low ductility materials, but a gap forms between the platform and blade that is difficult to seal causing uncontrolled leakage
Solution Approach 1:
The patent merges the previously separate platform and blade components into a single integral CMC structure. The platform and blade are both manufactured from ceramic matrix composite materials and formed as one continuous piece, eliminating the interface gap that caused sealing problems while maintaining the benefits of CMC material usage throughout the entire component.
Solution Approach 2:
The patent applies homogeneity by using the same CMC material for both the platform and blade portions. This eliminates material interfaces and ensures uniform properties throughout the structure, resolving the sealing issue caused by gaps between dissimilar materials while maintaining manufacturability with low ductility CMC materials.
2Temperature
If CMC materials are used for the airfoil and base, then high-temperature performance is improved, but the low tensile ductility of CMC materials creates manufacturing limitations
Solution Approach 1:
The patent changes the manufacturing parameters and process conditions to accommodate CMC material properties. By using specialized forming techniques, controlled curing cycles, and precise dimensional control during manufacturing, the patent overcomes the low ductility limitation while maintaining the high-temperature performance benefits of CMC materials throughout the platform and blade.
3Ease of manufacture
If a gap exists between the platform and blade, then manufacturing with separate components is easier, but uncontrolled leakage occurs affecting engine efficiency
Solution Approach 1:
The patent combines the platform and blade into a single integral component manufactured from CMC materials. This eliminates the gap that caused energy leakage while the manufacturing process is adapted to form the complex integral geometry in one piece, resolving both the sealing issue and maintaining manufacturability through advanced forming techniques.
Data Source
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AI summary
A composite blading member (10) includes an airfoil (12) and a base (20) of composite material layers (40) and a platform (38) of composite material layers (40) interfused with the airfoil (12) and base (20). The platform (38) comprises a platform shelf (42) and a plurality of spaced-apart platform supports (44,46) integral with the platform shelf (42) and interfused with surfaces (26,28) of the base. Such blading member (10) was made by providing a partially cured airfoil-base preform (36) and a platform perform (38), including an airfoil shaped opening (43) therethrough and preforms of the platform supports (44,46). The airfoil-base preform (36) was inserted through the airfoil shaped opening (43) whereby cooperating surfaces of the platform perform (38) and airfoil-based preform (36) were in juxtaposition. The performs (36,38) were heated to partially cure them together. Then they were interfused with a binder compatible with material of the preforms (36,38) under conditions to substantially fully cure the structures.