Annular Combustion Chamber Assembly Segmentation
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Solution Overview
Problem
The existing methods for assembling annular combustion chamber assemblies in gas turbine engines face challenges in efficiently securing and aligning combustion chamber segments, particularly in managing thermal expansion and radial loads, which can lead to stress and potential dislocation during operation.
Innovation Solution
The method involves positioning and removably securing combustion chamber segments around rings with hooks and slots, allowing for differential thermal expansion and providing a large surface area for radial restraint, using bolts and nuts to secure the segments to the upstream and downstream rings and the upstream end wall, and optionally including heat shields for protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If combustion chamber segments are rigidly secured to rings and end walls, then structural stability is improved, but thermal expansion stress increases and can cause dislocation
Solution Approach 1:
The patent employs hooks that can pivot or rotate within slots, transforming the rigid connection into a dynamic one. This allows the combustion chamber segments to move slightly with thermal expansion while maintaining overall structural stability, resolving the contradiction between rigidity and thermal stress.
Solution Approach 2:
The connection mechanism allows for parameter changes in position and orientation of the segments relative to the rings and end walls. The slots provide a range of motion that accommodates thermal expansion, enabling the system to adapt to changing temperature conditions without excessive stress.
2Stability of the object's composition
If multiple bolts and nuts are used to secure segments, then radial restraint is improved, but assembly complexity increases
Solution Approach 1:
The combustion chamber is divided into multiple segments that can be assembled independently around the rings. Each segment has its own hooks and connection points, allowing for modular assembly that maintains radial restraint while simplifying the overall assembly process compared to a fully bolted construction.
Solution Approach 2:
The hooks act as intermediary elements between the segments and the rings/end walls. These hooks provide a simplified connection mechanism that achieves radial restraint without requiring multiple bolts and nuts at each connection point, reducing assembly complexity while maintaining stability.
3Manufacturing precision
If segments are made as single integral pieces, then manufacturing precision is improved, but ease of repair and replacement deteriorates
Solution Approach 1:
The combustion chamber is segmented into multiple removable sections that can be independently accessed, removed, and replaced. This segmentation maintains manufacturing precision for each individual segment while dramatically improving ease of repair and maintenance, as damaged segments can be replaced without disassembling the entire structure.
Solution Approach 2:
The hooks and connection mechanisms are designed to facilitate preliminary positioning and alignment of segments during assembly and maintenance. This preliminary action ensures proper alignment and manufacturing precision is maintained while enabling easy removal and replacement of segments for repair.
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 method enhances the assembly's stability and durability by allowing for differential thermal expansion and radial restraint, reducing stress on the segments and enabling easier maintenance and replacement, while maintaining efficient operation during high-load conditions.
Implementation Method 1
The first hook extends circumferentially away from the first combustion chamber segment... allowing for differential thermal expansion
Implementation Method 2
removably securing the downstream end of each first combustion chamber segment to the first ring... removably securing the upstream end of each first combustion chamber segment of the first assembly to the annular upstream end wall
Data Source
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AI summary
A method of assembling an annular combustion chamber assembly (15) comprises the steps of: a) positioning a plurality of first combustion chamber segments (60) circumferentially side by side to form an annulus and removably securing the downstream end of each first combustion chamber segment (60) to a first ring (56) to form a first assembly (142), b) positioning a plurality of second combustion chamber segments (58) circumferentially side by side to form an annulus, removably securing the downstream end of each second combustion chamber segment (58) to a second ring (54) to form a second assembly (140), c) removably securing the upstream end of each second combustion chamber segment (58) of the second assembly (140) to an annular upstream end wall (43), d) inserting the second assembly (140) into the first assembly (142), and e) removably securing the upstream end of each first combustion chamber segment (60) of the first assembly (142) to the annular upstream end wall (43) to form the annular combustion chamber assembly (15).