CMC Endwall Contouring With Ceramic Inserts for Vortex Loss Reduction
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Solution Overview
Problem
Existing methods for manufacturing ceramic matrix composite (CMC) components with high precision endwall contouring in gas turbine engines are non-trivial, leading to significant aerodynamic losses due to horseshoe vortices at the endwalls.
Innovation Solution
A method involving the use of a contoured ceramic insert between fiber layers to define the endwall contour, with the outer fiber layer conforming to the contoured surface, followed by densification to create a CMC airfoil endwall with precise geometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional casting or machining methods are used to create endwall contouring in metallic materials, then high precision contouring can be achieved, but the complexity of manufacturing CMC components with similar precision becomes non-trivial
Solution Approach 1:
A contoured insert is prepared in advance with the desired endwall geometry before assembly. This preliminary preparation of the contouring feature allows the complex geometry to be built into the mold or tooling structure beforehand, simplifying the overall manufacturing process while maintaining high precision.
Solution Approach 2:
A contoured insert acts as an intermediary tool or mold cavity that transfers the precise endwall contouring geometry to the CMC material. This intermediary component enables the transfer of complex 3D geometry without requiring direct machining of the final part, reducing manufacturing complexity.
2Loss of energy
If endwall contouring is not implemented, then the manufacturing process remains simple, but aerodynamic losses increase due to horseshoe vortices
Solution Approach 1:
The endwall contouring is applied locally at specific regions where horseshoe vortices form and cause maximum loss. By targeting only the critical areas for contouring rather than redesigning the entire endwall, the solution reduces aerodynamic loss while minimizing the added complexity of the geometry.
Solution Approach 2:
The endwall contouring incorporates curved surfaces and rounded transitions to eliminate sharp corners and abrupt changes in geometry. These curved profiles reduce the formation of horseshoe vortices by smooth flow transitions, thereby reducing aerodynamic loss while maintaining manufacturability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables high-precision endwall contouring in CMC components, reducing aerodynamic losses and improving engine efficiency by minimizing horseshoe vortices.
Implementation Method 1
the second fiber layer conforms to a contoured surface of the contoured insert such that the contoured surface defines a geometry of the gas path surface
Implementation Method 2
densifying the assembled ceramic insert and first fiber ply
Data Source
AI summary
An endwall assembly for an airfoil of a gas turbine engine includes a first fiber layer, a second fiber layer forming a gas path surface, and a contoured insert disposed between the first and second fiber layers, wherein the second fiber layer conforms to a contoured surface of the contoured insert such that the contoured surface defines a geometry of the gas path surface.