Annular Combustion Chamber CMC Manufacturing
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Solution Overview
Problem
The production of annular combustion chambers for gas turbine engines using composite materials, particularly thermostructural composites, poses challenges due to severe mechanical and thermal stresses and the complex shape of the hollow ring structure, which has not been previously addressed in manufacturing methods.
Innovation Solution
A method involving the use of a shaping tool with movable slides to manufacture a one-piece annular combustion chamber, where the chamber is formed around the tool, and the slides are removed through a predetermined order and opening, allowing for the production of a structurally efficient, hollow part with variable thickness, eliminating the need for counter-moulds and external shaping pieces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a traditional moulded or welded solution is used for the annular combustion chamber, then the manufacturing process is simpler, but the structural efficiency and thermal-mechanical performance are insufficient
Solution Approach 1:
The combustion chamber is divided into multiple modular segments that can be manufactured separately and then assembled. This segmentation allows each module to be optimized for structural efficiency while maintaining ease of manufacturing through standardized production processes.
Solution Approach 2:
The patent employs composite materials with optimized fiber orientations and material properties to achieve superior structural efficiency and thermal-mechanical performance. The composite structure allows for tailored mechanical properties in different directions to withstand the severe operating conditions.
2Reliability
If the combustion chamber is manufactured as a one-piece assembly, then the structural integrity is improved, but the manufacturing complexity and tooling requirements increase
Solution Approach 1:
The one-piece combustion chamber is segmented into multiple sections during manufacturing, allowing for simpler tooling and production processes. The segments are then joined using advanced connection techniques to achieve the structural integrity of a one-piece construction.
Solution Approach 2:
The patent introduces a new manufacturing dimension by using complex forming tools and processes that enable the production of monolithic structures with integrated features, reducing the need for post-assembly operations while maintaining structural integrity.
3Ease of manufacture
If slides are removed from the hollow interior of the combustion chamber, then the manufacturing flexibility is improved, but the risk of damaging the chamber structure increases
Solution Approach 1:
The slides are designed with preliminary extraction features such as tapered surfaces and clearance gaps that enable their removal before the combustion chamber is fully cured or set. This preliminary design consideration allows for easy slide extraction without requiring forceful removal that could damage the chamber structure.
Solution Approach 2:
The patent introduces intermediary elements such as extraction channels or temporary support structures that facilitate the removal of slides from the hollow interior. These intermediaries provide a controlled path for slide extraction while protecting the chamber walls from damage during the removal process.
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 enables the production of a one-piece, thermally protected annular combustion chamber with improved mechanical and thermal stress resistance, integrating gas outlets and fuel injection devices, and eliminates the need for additional shaping tools, facilitating easier assembly and reducing material costs.
Implementation Method 1
impregnating the yarns or cords of the fibrous preform with a consolidating composition containing a carbon or ceramic precursor and by transforming the carbon or ceramic precursor by pyrolysis
Implementation Method 2
densified by chemical vapour infiltration
Data Source
AI summary
A method for producing an annular combustion chamber of a turbojet using CMC. For this, a shaping tool with movable slides is used and said chamber is produced around the tool, thereby producing a fibrous preform of which the shape is consolidated by drape moulding on the tool and pyrolysis, which is then densified by CVI. Several slides have back drafts, at least one other of such slides having a draft or neither a draft nor a back draft. Then, the slides are removed in a predetermined order imposed by the back drafts and the relative positions of the slides.