Gradient Metal-Ceramic Gas Turbine Combustor
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Solution Overview
Problem
Gas turbine engine components made of ceramics are brittle and prone to breaking under stress, especially in high-temperature environments, due to their rigid nature, which limits their application in combustor sections.
Innovation Solution
A blended structure combining ceramic and metal portions with a gradient transition, where the composition smoothly transitions from 100% metal to 100% ceramic, reducing stress caused by thermal expansion differences and enhancing thermal capabilities, using additive manufacturing techniques like direct metal laser sintering to create a seamless transition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ceramic materials are used in combustor sections, then high-temperature resistance is improved, but brittleness and susceptibility to breaking under stress worsens
Solution Approach 1:
The patent applies composite materials by creating a gradient structure that transitions from pure metal at the mounting points to pure ceramic at the hot-facing surfaces. This composite approach combines the high-temperature resistance of ceramics with the ductility and stress tolerance of metals, resolving the contradiction between thermal capability and mechanical strength.
Solution Approach 2:
The patent implements local quality by varying the material composition at different locations within the component. The mounting points contain primarily metal for ductility, while the hot-facing surfaces contain primarily ceramic for heat resistance, with a gradual transition zone in between. This spatial variation in material properties resolves the contradiction by optimizing each region for its specific functional requirements.
2Temperature
If pure ceramic components are used, then thermal capabilities are improved, but reliability under stress worsens
Solution Approach 1:
The gradient composite structure combines ceramic and metal phases in varying proportions throughout the component volume. The metal-rich regions provide reliability under stress while the ceramic-rich regions provide thermal capabilities, achieving both objectives simultaneously through the composite architecture.
Solution Approach 2:
The patent changes the material composition parameter gradually from one end of the component to the other. By varying the ceramic-to-metal ratio as a continuous parameter through the gradient structure, the component achieves optimal reliability in metal-rich zones and optimal thermal capability in ceramic-rich zones.
3Stress or pressure
If gradient transition structure is implemented, then stress from thermal expansion differences is reduced, but manufacturing complexity increases
Solution Approach 1:
The gradient transition structure implements a continuous change in material composition parameter from metal-rich to ceramic-rich phases. This gradual parameter change reduces thermal expansion stress by avoiding abrupt interfaces, while the additive manufacturing process manages the manufacturing complexity through digital modeling and layer-by-layer fabrication.
Solution Approach 2:
Each local region of the gradient structure has optimized quality appropriate to its position: metal-rich regions handle stress, ceramic-rich regions handle heat, and transition regions manage the gradient. This local optimization reduces overall stress while the additive manufacturing process handles the complexity of creating such a non-uniform structure.
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
The blended structure provides enhanced thermal capabilities and robust attachment points, effectively mitigating the brittleness of ceramics while maintaining high-temperature resistance, thereby improving the durability and performance of gas turbine engine components.
Implementation Method 1
reducing stress caused by thermal expansion differences
Implementation Method 2
using additive manufacturing techniques like direct metal laser sintering to create a seamless transition
Data Source
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AI summary
A combustor (56; 100) is provided. The combustor (56; 100) may comprise a shell (108, 110) including a ceramic material. A gradient transition (122, 128, 138; 154) from ceramic to metal may have a predominantly ceramic side coupled to the shell (108, 110). A metal mating surface (120, 126, 140) may also be coupled to a predominantly metal side of the gradient transition (122, 128, 138; 154) from ceramic to metal.