Compressor Stator Vane Assembly With Stress-Relieved Outer Shroud
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Solution Overview
Problem
Aircraft turbomachine compressors experience significant mechanical stresses on the outer shell due to the attachment of stator blades, which are traditionally fixed to both the inner and outer shells, leading to potential mechanical failure and air leaks.
Innovation Solution
The stator blades are fixed only to the inner ferrule, with non-immobilizing mechanical contact to the outer ferrule, and an axial groove in the outer ferrule to facilitate mounting, while a flexible sealing element prevents air leaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If stator blades are fixed to both the inner ferrule and the outer ferrule, then the mechanical strength and stability of the blade support structure is improved, but the mechanical stress on the outer ferrule increases significantly
Solution Approach 1:
The patent extracts the fixing function from the outer ferrule, leaving it with only a non-immobilizing mechanical contact. The stator blades are fixed exclusively to the inner ferrule, removing the source of concentrated mechanical stress from the outer ferrule while maintaining blade stability through the inner ferrule attachment alone.
Solution Approach 2:
The patent segments the support function between two separate components: the inner ferrule provides rigid fixation for the stator blades, while the outer ferrule provides a non-immobilizing contact that guides blade movement without bearing fixation loads. This segmentation allows each component to perform its specific function optimally without subjecting either to excessive stress.
2Ease of manufacture
If the groove in the outer ferrule extends axially to the downstream end, then the ease of mounting blades is improved, but the structural rigidity of the outer ferrule may be reduced
Solution Approach 1:
The groove is provided with localized reinforcement ribs that maintain structural rigidity in critical areas while allowing the groove to extend axially to the downstream end for ease of mounting. The reinforcement ribs are strategically positioned to compensate for the material removed by the groove, ensuring that the outer ferrule maintains sufficient structural strength.
3Stress or pressure
If stator blades are in non-immobilizing mechanical contact with the outer ferrule, then the mechanical stress transmission is reduced, but air leaks between the blade and outer ferrule may occur
Solution Approach 1:
The patent introduces a sealing element as an intermediary component between the stator blades and the outer ferrule. This sealing element prevents air leaks while allowing the non-immobilizing mechanical contact to maintain reduced stress transmission. The sealing element fills the gap between the blade and outer ferrule, blocking the air leak path without creating a rigid mechanical connection.
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 configuration reduces mechanical stresses on the outer ferrule, enhances mounting ease, and prevents air leaks, resulting in a more robust and efficient turbomachine compressor design.
Implementation Method 1
The sealing element is made of a flexible material in contact with the radially external ends of the stator blades. The flexible material preferably has a Young's modulus of less than 10 GPa.
Data Source
Figure 1
Figure 2~3c
Figure 4
AI summary
The present invention relates to a stator vane assembly (1) for a compressor (120, 130) of an aircraft turbine engine (100). The assembly comprises an inner shroud (20), an outer shroud (30) and stator vanes (10) attached only to the inner shroud (20) and in non-immobilizing mechanical contact with the outer shroud (30).