Gas Turbine Combustion Chamber Refractory Guide
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Solution Overview
Problem
The combustion chamber of gas turbomachines faces issues with thermal stress, mechanical deformation, parasitic gas leaks, pollution, fuel consumption, and re-ignition due to clearance between annular walls, and challenges in fixing energy supply elements on refractory material walls, which affects ignition and mechanical strength.
Innovation Solution
A one-piece assembly of refractory material, including a deflector and annular walls, with a metal flange and floating ring for guiding energy supply elements, and an intermediate fixing ring to secure the guide device without overstressing the refractory material, along with a barrel and flange design to facilitate assembly and reduce mechanical weakening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a deflector is mounted downstream of the chamber bottom to protect it thermally, then thermal protection of the chamber bottom is improved, but clearances appear between the deflector and annular walls which generate parasitic gas leaks and pollution
Solution Approach 1:
The deflector is designed with an asymmetric profile where the upstream face is positioned closer to the chamber bottom than the downstream face, creating an overlapping configuration with the annular walls. This asymmetric positioning eliminates clearances and prevents parasitic gas leaks while maintaining thermal protection functionality.
2Temperature
If the annular walls are made of refractory material to resist thermal stress, then thermal resistance is improved, but fixing the guide device for energy supply elements becomes complex due to difficulty in fixing on refractory material walls
Solution Approach 1:
The guide device is segmented into modular components: a guide portion that interfaces with the refractory annular wall, a floating ring component, and a flange component. This segmentation allows each part to be optimized for its specific function and facilitates assembly on refractory material surfaces through specialized fixing mechanisms like threading or adhesive bonding on the guide portion.
Solution Approach 2:
The guide portion of the guide device serves as an intermediary element that bridges the refractory annular wall and the floating ring mechanism. It provides a dedicated interface with threading or bonding surfaces that make fixing to refractory material practical, while the floating ring provides the actual guiding function for the energy supply element.
3Stability of the object's composition
If the guide device uses a metal flange and floating ring to guide the energy supply element, then compensation for thermal expansion and relative movement is improved, but mechanical stress on the refractory material wall increases
Solution Approach 1:
The guide device incorporates a floating ring that can move dynamically within the guide portion to accommodate thermal expansion and relative movement between components. This dynamic adjustment mechanism compensates for dimensional changes without transmitting excessive mechanical stress to the refractory annular wall, maintaining both stability and stress management.
Data Source
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AI summary
The invention relates to a combustion chamber for a gas turbine engine, in which two openings extend through a metal wall (58) and a wall made of a refractory material (16). A device (76) guides a spark plug (48) in said two orifices, the guiding device comprising a metal flange (80) and a floating ring (82), the flange being shrunk onto or welded to the metal wall (58).