CMC Combustor Tile with Embedded Ceramic Connectors
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Solution Overview
Problem
The existing support structures for ceramic matrix composite (CMC) liners in gas turbine engines experience structural stresses due to thermal expansion differences between the metal support structures and CMC liners, which limits the operational temperature and efficiency of the engines.
Innovation Solution
An annular assembly is developed comprising a metal supporting member with a ceramic matrix composite liner tile, where a connecting member with a base element embedded in the tile and a stem passing through a support hole of the supporting member is used to create an integrated structure that allows for thermal expansion and reduces structural stresses, with additional features like varying support hole orientations to permit movement and maintain distance between the tile and the supporting member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional metal support structures are used for CMC liners, then the structure can be manufactured with existing technologies, but thermal expansion differences create structural stresses that limit operational temperature
Solution Approach 1:
The support structure is divided into multiple segments or sections that can move independently relative to each other. This segmentation allows different parts of the support structure to accommodate thermal expansion differently, reducing overall structural stress while maintaining support for the CMC liner at higher temperatures.
Solution Approach 2:
The support structure incorporates features that change their physical parameters in response to temperature changes. This includes using materials or structures with varying thermal expansion coefficients, or designing geometric configurations that adapt to thermal conditions, allowing the structure to maintain integrity across a wider temperature range.
2Productivity
If CMC liners are used to withstand higher temperatures, then engine efficiency increases, but the thermal expansion difference with metal support structures creates additional structural stresses
Solution Approach 1:
The support structure transitions from a rigid, fixed configuration to a dynamic system that can adapt to thermal conditions. This includes incorporating movable joints, expandable sections, or flexible connections that allow the support structure to change its configuration in response to thermal expansion, maintaining structural integrity while supporting the CMC liner at high temperatures that improve engine efficiency.
3Stability of the object's composition
If the support structure is made more rigid to reduce thermal expansion stress, then structural stability improves, but the ability to accommodate thermal expansion decreases
Solution Approach 1:
The support structure is designed with pre-configured features that anticipate thermal expansion before it occurs. This includes pre-installed expansion joints, predetermined flexible connection points, or materials with controlled thermal properties that are selected in advance to accommodate expected thermal conditions, maintaining both stability and adaptability.
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 solution enables the CMC tiles to withstand higher temperatures, reduces thermal expansion stresses, and increases the efficiency of gas turbine engines by allowing operation at higher temperatures while minimizing structural stresses and weight.
Implementation Method 1
Due to the temperature difference between the liner and the support structure, and the forces generated by the products of combustion, the support structure may thermally expand at a different rate than the liner, creating additional structural stresses.
Implementation Method 2
The liner may be comprised of or coated with insulation materials.
Implementation Method 3
The combustor receives compressed air from the compressor and fuel from a fuel injector and includes a combustion chamber where the compressed air and the fuel are mixed and ignited. The combustion chamber may experience temperatures greater than 1,900° F. during the combustion process.
Data Source
AI summary
An annular assembly for a gas turbine engine and a method of making the annular assembly. The annular assembly comprises a supporting member comprising metal and including a support hole therethrough, and a liner tile made of ceramic matrix composite material. A plurality of the liner tile form an annular liner to shield hot combustion gases produced by the gas turbine engine. The liner tile is disposed adjacent the supporting member. A connecting member comprising ceramic material has a base element and a stem. The base element is embedded in the liner tile during construction of the liner tile to form an integrated structure therewith. A distal end of the stem passes through the support hole and is mated with a retaining member to retain the liner tile adjacent the supporting member.