Segmented CMC Turbine Blade for Porosity Reduction
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Solution Overview
Problem
Current ceramic matrix composite (CMC) materials for gas turbine engine components face challenges in producing thick parts due to manufacturing limitations, leading to porosity and difficulties in creating complex three-dimensional shapes, which affects heat transfer and strength, especially in high-temperature and high-stress environments.
Innovation Solution
The solution involves segmenting CMC components into axially stacked and abutting segments with radially elongate ceramic matrix composite material plates, each with a root portion for radial retention, allowing for optimal heat transfer and strength characteristics by fully densifying the material and aligning fibers for maximum tensile strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If CMC material is used to reduce weight and increase heat resistance, then weight is reduced and temperature limitations are increased, but manufacturing complexity increases and production limitations arise
Solution Approach 1:
The turbine blade is divided into multiple axially stacked segments (leading edge segment, middle segments, trailing edge segment, platform segment) that can be manufactured separately and then assembled. This segmentation allows each segment to be produced within feasible manufacturing thickness limits while maintaining the overall benefits of CMC material usage.
2Productivity
If thick CMC parts are produced to reduce component数量, then manufacturing constraints increase leading to porosity and crack initiation, but component integration is improved
Solution Approach 1:
The blade is segmented into multiple thinner sections that can be fully densified during manufacturing. By keeping each segment within the maximum feasible thickness for complete liquid matrix infusion, porosity is eliminated while the segments are subsequently assembled to form the complete blade structure.
3Strength
If CMC components are produced as single pieces, then structural integrity is improved, but manufacturing limitations prevent complex three-dimensional shapes
Solution Approach 1:
The complex three-dimensional blade geometry is achieved by assembling multiple segments, each with optimized fiber orientation and shape. The segments include a leading edge segment with fibers oriented for leading edge strength, middle segments with radial fiber orientation, and a platform segment with specific geometry for rotor engagement.
Solution Approach 2:
Each segment is constructed as a ceramic matrix composite with specifically oriented ceramic fabric and infused liquid matrix. The composite structure provides both the strength required for structural integrity and the manufacturing feasibility for complex shapes through controlled fiber orientation in each segment.
4Strength
If radially stacked CMC layers are compressed with mechanical tensioning means, then tensile strength is obtained, but the design becomes impractical for rotating turbine blades due to stress direction
Solution Approach 1:
Instead of stacking layers radially and compressing them perpendicular to the rotation axis, the invention inverts the approach by stacking segments axially and orienting the ceramic fibers radially. This allows the fibers to directly resist the centrifugal tensile stresses in the radial direction without requiring complex mechanical tensioning means.
Data Source
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AI summary
A segmented component (12, 14) for use with a gas turbine engine comprises a radially extending gas path portion (12B). The gas path portion is for interacting with gas flow from the gas turbine engine. The component is divided into axially aligned segments comprising a forward segment (24A), an aft segment (24B), and a plurality of middle segments (24C) disposed between the forward segment and the aft segment. The middle segments comprise radially elongate ceramic matrix composite material plates. In one embodiment, the gas path portion comprises an airfoil for a turbine blade. In another embodiment, the gas path portion comprises a removable platform for a turbine blade. In another embodiment, the gas path portion comprises an airfoil for a turbine vane.