Swirler Pseudo-Dome Interface for CMC Combustor Thermal Decoupling
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Solution Overview
Problem
The integration of a metallic swirler with a Ceramic Matrix Composite (CMC) dome in gas turbine engines poses challenges in connecting the metallic swirler to the CMC dome while providing thermal decoupling between the two materials, as conventional metallic dome structures require cooling and a deflector wall, which are not necessary with CMC materials, leading to length reductions but complicating the interface.
Innovation Solution
A metallic swirler is separately mounted to a pseudo-dome structure, which is then connected to the CMC dome, allowing the swirler assembly to interface with the CMC dome without direct attachment, enabling thermal decoupling and reducing the overall axial length of the combustor module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a metallic swirler is directly attached to a CMC dome, then structural integrity is maintained, but thermal decoupling is compromised and cooling requirements increase
Solution Approach 1:
A pseudo-dome structure serves as an intermediary component between the metallic swirler and the CMC dome. This pseudo-dome is attached to the swirler and interfaces with the CMC dome, providing thermal decoupling while maintaining structural integrity. The intermediary structure allows the metallic swirler to be thermally isolated from the CMC dome, reducing cooling requirements for the CMC dome while preserving the structural connection needed for mechanical support.
2Length of moving object
If a metallic dome structure is used with deflector wall and cooling holes, then thermal management is achieved, but axial length is reduced when using CMC materials
Solution Approach 1:
The dome structure is segmented into two functional parts: a pseudo-dome structure that interfaces with the metallic swirler, and a CMC dome that provides the combustion chamber boundary. This segmentation allows each component to be optimized independently - the pseudo-dome handles the thermal management functions previously requiring a full metallic dome, while the CMC dome benefits from its inherent thermal properties and reduced cooling requirements, ultimately reducing the overall axial length.
3Temperature
If cooling holes are included through the dome structure, then surface cooling is provided, but air availability for other purposes is reduced
Solution Approach 1:
The pseudo-dome structure acts as a thermal intermediary that provides the necessary cooling functions without requiring extensive cooling holes in the CMC dome. By absorbing and managing thermal loads through its own structure and interface with the metallic swirler, the pseudo-dome reduces the cooling demand on the CMC dome, thereby preserving air availability for combustion and other operational purposes.
Data Source
AI summary
A combustor for a gas turbine includes a cowl structure, a pseudo-dome structure, a ceramic matrix composite (CMC) dome, and a swirler assembly. The swirler assembly is connected to the pseudo-dome structure, which is connected to the cowl structure, and the CMC dome is separately connected to the cowl structure apart from the swirler assembly. The swirler assembly includes a swirler dome interface wall that interfaces with the CMC dome on an upstream side of the CMC dome, and a swirler outlet extends through a CMC dome swirler opening through the CMC dome.