Annular CMC Interface for Combustor Liner Thermal Mismatch
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in gas turbine engines is the different thermal growth rates of ceramic matrix composite (CMC) and metal components in combustor liners, which can lead to stress and inefficiencies due to their varying expansion rates during combustion.
Innovation Solution
An annular ceramic matrix composite (CMC) interface is designed with inner and outer joint grooves to accommodate both CMC and metal skins, allowing for differential thermal expansion while maintaining a continuous CMC surface and supporting the metal shell, thus mitigating thermal mismatch and stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If CMC and metal components are used together in combustor liners, then the combustor can sustain high temperatures, but different thermal growth rates cause stress and inefficiencies
Solution Approach 1:
The combustor liner is segmented into distinct CMC and metal components with independent expansion capabilities. The CMC inner skin and metal outer skin are separated by a gap, allowing each material to expand independently according to its thermal growth rate, thereby eliminating thermal stress while maintaining high-temperature sustainability.
Solution Approach 2:
A gap or spacing mechanism acts as an intermediary between the CMC and metal skins, enabling differential thermal expansion without direct mechanical constraint. This intermediary space allows each material to respond independently to temperature changes, resolving the thermal stress issue while preserving the high-temperature operational capability.
2Strength
If CMC and metal skins are bonded together, then structural integrity is maintained, but thermal expansion mismatch causes stress
Solution Approach 1:
The skin structure is segmented into separate CMC and metal layers rather than being bonded as a composite. This segmentation allows each layer to expand independently, maintaining structural integrity through the layered configuration while eliminating thermal mismatch stress through independent thermal response.
Solution Approach 2:
The design changes the thermal expansion parameter relationship by introducing a gap between materials, allowing each material to exhibit its natural thermal expansion behavior without constraint. This parameter change from bonded to spaced configuration resolves the thermal stress problem while preserving structural integrity through the maintained layered structure.
3Stress or pressure
If a single-material liner is used, then thermal expansion is uniform, but high-temperature resistance is compromised
Solution Approach 1:
The combustor liner uses a composite configuration combining CMC and metal materials with different thermal properties. The CMC inner skin provides high-temperature resistance while the metal outer skin provides structural support, and the gap between them allows independent thermal expansion, achieving both high-temperature resistance and uniform thermal expansion behavior.
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 solution effectively manages thermal expansion differences between CMC and metal components, ensuring efficient operation and durability of the combustor liners by allowing for axial and radial movement, thereby reducing thermal stresses and maintaining the structural integrity of the combustor.
Implementation Method 1
The challenge in gas turbine engines is the different thermal growth rates of ceramic matrix composite (CMC) and metal components in combustor liners, which can lead to stress and inefficiencies due to their varying expansion rates during combustion.
Data Source
AI summary
An interface for double-skin combustor liner comprises an annular ceramic matrix composite (CMC) body. The annular body extends from a first side to a second side, the first and second sides each having an annular inner joint groove configured to receive a CMC combustor skin and an annular outer joint groove configured to receive a metal combustor skin. The outer joint groove is radially outward of the inner joint groove. A combustor and an gas turbine engine with the interface are also provided.