Ceramic Combustor Liner with Resilient Support
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Solution Overview
Problem
Current gas turbine engine combustors face challenges with metallic heat shields failing due to high temperatures and ceramic matrix composite materials experiencing cracking or breakage from threaded holes, which are prone to local flaws.
Innovation Solution
A combustor design utilizing a ceramic matrix composite material with a resilient support structure, including spring members to mitigate thermal mismatch and facilitate impingement cooling, eliminating the need for a conventional metallic heat shield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ceramic materials are used for the heat shield to increase heat resistance, then temperature resistance is improved, but strength capacity deteriorates due to decreased ability to withstand mechanical loads and susceptibility to cracking from threaded holes
Solution Approach 1:
The patent employs a composite structure consisting of a ceramic matrix composite liner (providing heat resistance) supported by a metallic support structure (providing mechanical strength). This composite approach allows the system to simultaneously achieve high temperature resistance and adequate strength capacity by combining materials with complementary properties.
Solution Approach 2:
The patent introduces a transition layer or interface structure between the ceramic liner and metallic support that acts as an intermediary. This intermediate structure mitigates the mechanical stress concentration at the interface and prevents crack propagation from the support structure into the ceramic liner, thereby preserving the ceramic's heat resistance while compensating for its lower strength capacity.
2Ease of manufacture
If threaded holes are introduced into ceramic structure to attach fasteners, then ease of assembly is improved, but reliability deteriorates due to local flaws that may lead to cracking or breakage
Solution Approach 1:
The patent introduces a transition layer or interface structure between the ceramic liner and metallic support that acts as an intermediary. This intermediate structure mitigates the mechanical stress concentration at the interface and prevents crack propagation from the support structure into the ceramic liner, thereby preserving the ceramic's heat resistance while compensating for its lower strength capacity.
Solution Approach 2:
The patent divides the support structure into modular segments that can be independently assembled. This segmentation allows for distributed attachment points that reduce the concentration of mechanical stresses at any single location, thereby maintaining reliability while enabling ease of assembly through modular construction.
3Strength
If metallic heat shield is used to carry thermal load, then strength capacity is improved, but heat resistance deteriorates leading to periodic replacement due to high temperature failure
Solution Approach 1:
The patent employs a composite structure consisting of a ceramic matrix composite liner (providing heat resistance) supported by a metallic support structure (providing mechanical strength). This composite approach allows the system to simultaneously achieve high temperature resistance and adequate strength capacity by combining materials with complementary properties.
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 design enhances the durability and heat resistance of the combustor by allowing axial and radial movement of the ceramic liner, reducing the risk of cracking and extending the lifespan of the components.
Implementation Method 1
the support includes at least one spring member arranged to resiliently support the liner
Implementation Method 2
the support includes perforations configured to facilitate impingement cooling of the combustor
Data Source
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AI summary
A combustor includes a liner and a support. The liner includes first and second spaced apart liner walls defining a combustion chamber therebetween, and an end wall joining the first and second liner walls at a forward end. The support is configured to resiliently support the liner and includes first and second spaced apart support walls having first and second retainers configured to capture aft ends of the first and second liner walls. A gas turbine engine and a method of assembling a combustor are also disclosed.