Turbojet Combustion Chamber Injection System Mechanical Retention
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Solution Overview
Problem
The existing fixing systems for injection systems in turbojet combustion chambers are prone to rupture, leading to potential engine explosions and are difficult to dismantle for maintenance or replacement, as they require removing multiple solders simultaneously, often resulting in the sacrifice of the injection system.
Innovation Solution
The deflector features an annular part with a retaining shoulder directed towards the front of the engine, and the injection system has a flange with a retaining shoulder directed towards the rear, mechanically retaining the deflector and injection system components, preventing them from being sucked into the combustion chamber, and facilitating easier maintenance by allowing weld seams to be broken without affecting other connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the injection system is mounted using solder connections to the chamber bottom, then the system achieves a compact and integrated structure, but the solder joints are prone to rupture under thermal and mechanical stress, causing components to be projected into the combustion chamber
Solution Approach 1:
The patent replaces the solder-based mechanical connection system with a mechanical fastening system using a retaining ring and retaining shoulder. The retaining ring (50) engages with the retaining groove (40) in the deflector (20) and the retaining shoulder (46) on the bowl (10), providing a mechanical connection that is far more reliable than solder joints under thermal and mechanical stress in the combustion chamber environment.
2Strength
If multiple solder joints are used to secure the injection system components, then the components are firmly attached, but dismantling requires removing all solders simultaneously which is complex and often requires sacrificing the injection system
Solution Approach 1:
The patent segments the attachment system into distinct mechanical elements: the retaining ring (50) as a separate removable component, the retaining groove (40) in the deflector (20), and the retaining shoulder (46) on the bowl (10). This segmentation allows the injection system to be securely attached during operation but easily dismantled by simply removing the retaining ring, without requiring removal of multiple solder joints or sacrificing any components.
3Device complexity
If the deflector is mounted from the downstream part of the chamber bottom, then the mounting structure is simplified, but the deflector cannot be mechanically retained to prevent it from being sucked into the combustion chamber in case of solder rupture
Solution Approach 1:
The patent introduces the retaining ring (50) as an intermediary mechanical retention element between the deflector (20) and the bowl (10). The retaining ring engages with the retaining groove in the deflector and the retaining shoulder on the bowl, providing a mechanical barrier that prevents the deflector from being sucked into the combustion chamber even if the solder joints fail. This intermediary element adds minimal complexity while dramatically improving reliability.
4Strength
If the injection system components are securely brazed together, then the assembly achieves high structural strength, but maintenance requires removing multiple strong bonds which is difficult and costly
Solution Approach 1:
The patent creates a dynamic attachment system where the retaining ring can be easily removed and reinstalled for maintenance operations. The mechanical connection allows the injection system to be securely attached during operation (high strength) but easily dismantled when maintenance is required (low removal effort), eliminating the need to break strong brazing joints and reducing maintenance time and costs.
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 design enhances safety by preventing engine components from being drawn into the combustion chamber in case of solder rupture and simplifies maintenance by allowing the injection system to be easily removed and replaced, reducing the risk of engine damage and improving maintenance efficiency.
Implementation Method 1
the deflector and the retaining ring are brazed in the same brazing operation
Implementation Method 2
The injection system is attached to the retaining ring by weld seams
Data Source
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AI summary
A system for attaching an injection system to the bottom of a turbojet combustion chamber. It includes a deflector (20) brazed onto the bottom of the chamber (22). The deflector has an annular portion (32) having an edge (42) forming a retaining shoulder directed towards the front of the turbojet, and the injection system (2) has a flange (44) on which is formed a retaining shoulder (46), directed towards the rear of the turbojet and bearing against the retaining shoulder (42) of the deflector (20).