Stator Blade Section Mixed Fixation for Axial Turbomachines
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Solution Overview
Problem
Existing methods for attaching stator blades to shrouds in axial turbomachines are either time-consuming, heavy due to the use of screws, or require multiple parts and types of blades, leading to rigidity and weight issues.
Innovation Solution
A method of fixing stator blades that uses a configuration where only the platforms of the lateral blades are equipped with fixing screws, while the central blade platform is free of screws, achieving a balance between rigidity and weight by reducing the number of screws and avoiding interference with casing elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fixing screws are used on all blade platforms, then the rigidity of the stator assembly is improved, but the weight increases significantly
Solution Approach 1:
The patent applies partial action by equipping only the central blade platform with fixing screws, while the lateral blade platforms remain without screws. This partial application of the fixing mechanism provides sufficient rigidity for the stator assembly while significantly reducing the total weight compared to equipping all platforms with screws.
2Strength
If fixing screws are used on all blade platforms, then the attachment strength is improved, but the assembly time increases
Solution Approach 1:
By applying the fixing screw mechanism only to the central blade platform rather than all platforms, the patent reduces the number of assembly operations required. This partial application maintains sufficient attachment strength while significantly reducing assembly time, especially for large diameter turbomachines with high numbers of blades.
3Reliability
If fixing screws are used on all blade platforms, then the fixation reliability is improved, but the device complexity increases
Solution Approach 1:
The patent reduces device complexity by applying the fixing mechanism only where absolutely necessary (central platform) rather than uniformly across all platforms. This selective application maintains fixation reliability for the critical central position while eliminating unnecessary complexity from lateral platforms.
Solution Approach 2:
The patent extracts the fixing screw mechanism from the lateral blade platforms, removing unnecessary components. This extraction simplifies the overall device structure while maintaining sufficient fixation reliability through the centralized fixing approach.
4Reliability
If fixing screws are used on all blade platforms, then the attachment reliability is improved, but the number of parts increases
Solution Approach 1:
The patent removes fixing screws from the lateral blade platforms, extracting unnecessary parts from the system. This reduction in the number of parts simplifies inventory management, assembly procedures, and maintenance while maintaining adequate attachment reliability through the central fixing mechanism.
Data Source
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AI summary
The invention relates to a sector of stator blades (28, 30) intended to be fixed to a housing (22) of an axial turbomachine, the sector comprising several blades with platforms (34) juxtaposed to describe an arc of a circle. At least one of the platforms has a fixing screw (32) on its outer face, and at least one other platform is free of fixing screws, the platforms (34) being fixed to each other at their adjacent edges. The invention also relates to a stator or stator section (5) comprising a housing forming a generally circular wall and blade sectors arranged along the wall. The housing comprises several portions (22) connected to each other by longitudinal flanges (24). The platforms free of fixing screws are arranged opposite the flanges (24).