Azimuthal Interlocking for Annular Combustion Chamber Sealing
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Solution Overview
Problem
Conventional turbomachine annular combustion chambers face issues with gas leaks, structural weakness, and maintenance difficulties due to assembly methods such as welding, axial interlocking, and bolting, which hinder efficient operation and longevity.
Innovation Solution
The implementation of azimuthal interlocking between complementary assembly means on the first and second annular walls, utilizing tongues and flanges that cooperate by rotation, providing a sealed, removable, and thermally adaptable assembly that reduces gas leaks and avoids crack formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welding is used to assemble the first and second annular walls, then the structural strength is improved, but the maintainability deteriorates because the walls cannot be dismantled
Solution Approach 1:
The combustion chamber is divided into separate modular sections (first and second annular walls) that can be independently removed and replaced, enabling maintenance without complete disassembly while maintaining structural integrity through designed connection interfaces
Solution Approach 2:
The assembly means are configured with nested or engaged structures that allow one wall to be fitted within or against the other through rotational movement, creating a secure connection that maintains strength while allowing for controlled disassembly and reassembly
2Ease of repair
If axial interlocking is used to assemble the first and second annular walls, then the maintainability is improved, but the reliability deteriorates due to combustion gas leaks through the fitting zones
Solution Approach 1:
The assembly transitions from axial interlocking to azimuthal (rotational) interlocking, changing the dimension of connection from linear to rotational, which enables the sealing surfaces to maintain continuous contact through radial thermal expansion while allowing for easy disassembly along the axial direction
3Ease of repair
If bolting is used to assemble the first and second annular walls, then the maintainability is improved, but the strength deteriorates due to crack formation near engagement holes
Solution Approach 1:
The design removes bolts and engagement holes from the structure, eliminating the source of crack initiation while maintaining the maintainability benefit through alternative azimuthal interlocking mechanisms that distribute stresses uniformly across the assembly interface
Solution Approach 2:
The connection method changes from mechanical fastening with concentrated stress points to a distributed interlocking system that accommodates thermal expansion and contraction, preventing the stress concentrations that lead to crack formation
4Ease of repair
If axial interlocking is used, then the maintainability is improved, but the reliability deteriorates due to significant combustion gas leaks
Solution Approach 1:
The assembly transitions from axial interlocking to azimuthal (rotational) interlocking, changing the dimension of connection from linear to rotational, which enables the sealing surfaces to maintain continuous contact through radial thermal expansion while allowing for easy disassembly along the axial direction
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 ensures zero or negligible gas leaks, facilitates easy maintenance, and enhances mechanical strength by maintaining contact between walls while accommodating thermal expansions, thus improving the reliability and longevity of the combustion chamber.
Implementation Method 1
the radial and axial thermal expansions are easily supported by the first and second complementary assembly means, which can slide while maintaining the interlocking with respect to each other. Thus, these slips make it possible on the one hand to compensate for thermal expansion while maintaining a satisfactory geometry of the assembly
Implementation Method 2
the first and second complementary assembly means being respectively complementary to each other of so as to be able to cooperate by interlocking... the cooperation of the complementary assembly means by azimuthal interlocking makes it possible to reduce combustion gas leaks compared to axial interlocking. Indeed, the radial thermal expansions being less important than the axial thermal expansions, an assembly by azimuth interlocking makes it possible to maintain a permanent contact between the first and the second annular wall
Data Source
Figure 1
Figure 1A~2
Figure 3
AI summary
Annular combustion chamber (10) of a turbomachine having an axial direction (X), a radial direction (R) and an azimuthal direction (Y), comprising a first annular wall (12) and a second annular wall (14), each annular wall delimiting at least a part of the enclosure of the combustion chamber (10). The first annular wall (12) and the second annular wall (14) have complementary assembly means (12b, 14b) that engage via azimuthal interlocking.