Integrally Formed CMC Combustor Dome and Liners
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Solution Overview
Problem
The attachment of ceramic matrix composite (CMC) materials in gas turbine engines poses challenges due to their different thermal expansion coefficients compared to metal materials, leading to complex and aerodynamically disruptive attachment assemblies in combustion chambers.
Innovation Solution
A combustor assembly with an integrally formed ceramic matrix composite combustor dome and liners, featuring transition portions and cooling holes, which allows for seamless integration and improved aerodynamics by eliminating seams and facilitating uniform thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If CMC materials are used for liners and dome in combustor assembly, then high temperature resistance is improved, but attachment complexity increases due to different thermal expansion coefficients
Solution Approach 1:
The patent merges the dome and liners into a single integrally formed CMC component, eliminating the need for separate attachment assemblies. This integration resolves the thermal expansion mismatch issue by using a uniform material throughout the combustion chamber structure, thereby maintaining high temperature resistance while eliminating attachment complexity.
Solution Approach 2:
The patent applies homogeneity by forming the entire combustion chamber structure (dome and liners) from the same CMC material with consistent properties. This uniform material composition ensures uniform thermal expansion characteristics throughout the structure, eliminating the need for complex differential expansion compensation mechanisms that would arise from joining dissimilar materials.
2Reliability
If complex attachment assemblies are used to join CMC liners to metal dome, then material compatibility is improved, but aerodynamic performance deteriorates due to flow disruption
Solution Approach 1:
By merging the dome and liners into a single integrally formed component, the patent eliminates the attachment assemblies that cause aerodynamic disruption. The seamless integration maintains material compatibility through uniform CMC construction while removing the harmful aerodynamic effects of mechanical joints, bolts, or other attachment hardware.
Solution Approach 2:
The patent extracts and eliminates the attachment assemblies from the combustor structure. By removing these intermediate joining components entirely and replacing them with an integrally formed design, the solution simultaneously resolves material compatibility concerns and eliminates aerodynamic disruption caused by attachment hardware.
3Ease of operation
If traditional metal dome is used for fuel-air injection assembly attachment, then ease of attachment is improved, but aerodynamic flow through combustion chamber deteriorates
Solution Approach 1:
The patent combines the fuel-air injection assembly attachment directly into the integrally formed CMC dome structure. This integration maintains ease of attachment by providing built-in mounting features within the seamless dome design, while simultaneously eliminating aerodynamic disruption by avoiding separate attachment assemblies that would interfere with combustion gas flow.
4Object-generated harmful factors
If CMC materials are used throughout combustor assembly, then aerodynamic performance is improved by eliminating seams, but manufacturing complexity increases
Solution Approach 1:
The patent merges the dome and liners into a single integrally formed CMC component, which eliminates seams and improves aerodynamic flow characteristics. While this may increase manufacturing complexity compared to assembling separate parts, the integral formation process is optimized for CMC manufacturing techniques, and the benefits of seamless aerodynamic performance justify the manufacturing approach.
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 configuration enhances the flow characteristics of combustion gases and cooling air within the combustion chamber, reducing pressure drops and enabling efficient thermal management without disrupting gas flow.
Implementation Method 1
the combustor dome defines a plurality of cooling holes extending through the transition portion from the cold side to the hot side to allow for a flow of cooling air
Implementation Method 2
CMC materials have different coefficients of thermal expansion than the traditional metal materials. Therefore, the attachment of the inner and outer liners, formed of a CMC material, to the dome, formed of a metal material, may require a fairly complicated attachment assembly
Data Source
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AI summary
A combustor assembly (100) for a gas turbine engine includes a liner (104, 106) and a combustor dome (102). The combustor dome (102) and liner (104, 106) together at least in part define a combustion chamber (108). The combustor dome (102) includes a transition portion (120, 122) and a forward wall (118). The transition portion (120, 122) extends from the forward wall (118) towards the liner (104, 106). Additionally, the transition portion (120, 122) may define an angle (132, 133) relative to the forward wall (118) and/or may define a radius of curvature (134, 136) between the forward wall (118) of the combustor dome (102) and a flat (128, 130) of the transition portion (120, 122) of the combustor dome (102) for increasing an aerodynamic efficiency of the combustor dome (102).