Ceramic Airfoil Trailing Edge Cooling via CMC Liner and Pedestals
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Solution Overview
Problem
The challenge in designing airfoils for gas turbine engines is to create a thin, strong, and efficiently cooled trailing edge that can withstand high temperatures and heat fluxes, while maintaining structural integrity and aerodynamic performance.
Innovation Solution
The airfoil features a trailing edge region with monolithic ceramic exterior walls, a ceramic matrix composite (CMC) liner, and an array of pedestals that bridge the liner and the exterior walls, forming a flow discharge passage with metering orifices to enhance cooling and structural support, allowing for effective heat transfer and mechanical strengthening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a thin trailing edge is designed to improve aerodynamic performance, then aerodynamic performance is improved, but structural strength deteriorates
Solution Approach 1:
The trailing edge uses a composite structure combining monolithic ceramic exterior walls with a CMC liner material. This composite configuration provides both the thin profile needed for aerodynamic performance and the structural strength through the combined properties of the ceramic walls and CMC core, resolving the contradiction between thinness and strength.
2Temperature
If cooling passages are added to improve cooling efficiency, then cooling efficiency is improved, but device complexity increases
Solution Approach 1:
The cooling system is segmented into multiple independent cooling passages formed within the CMC liner material, allowing cooling fluid to flow through separate channels. This segmentation enables efficient cooling of different regions of the trailing edge while maintaining a relatively simple overall structure, as the passages are integrated into the liner rather than requiring external cooling components.
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
This configuration provides a thin, strong, and efficiently cooled trailing edge that maintains structural integrity and aerodynamic performance, facilitating high temperature operability with improved cooling and heat transfer, while minimizing pressure loss and enhancing convective heat transfer.
Implementation Method 1
an array of pedestals disposed in the flow discharge passage. Each pedestal bridges the CMC liner and at least one of the first and second monolithic ceramic exterior walls
Implementation Method 2
Metering orifices are disposed where the first and second CMC liner walls meet. The metering orifices in the first monolithic ceramic exterior wall lead to the first sub-passage, and the metering orifices in the second monolithic ceramic exterior wall lead to the second sub-passage
Implementation Method 3
This configuration provides a thin, strong, and efficiently cooled trailing edge that maintains structural integrity and aerodynamic performance, facilitating high temperature operability with improved cooling and heat transfer
Data Source
Figure 1
Figure 2~3
Figure 4A~5
AI summary
An airfoil (58) includes an airfoil body (60) that has a trailing edge region (62). The trailing edge region (62) includes first and second monolithic ceramic exterior walls (64a, 64b), a flow discharge passage (70) between the first and second monolithic ceramic exterior walls (64a, 64b), a ceramic matrix composite (CMC) liner (66) at least a portion of which is disposed in the flow discharge passage (70) between the first and second monolithic ceramic exterior walls (64a, 64b), and an array of pedestals (72) disposed in the flow discharge passage (70). Each of the flow guides bridges the CMC liner (66) and at least one of the first and second monolithic ceramic exterior walls (64a, 64b).