Gas Turbine Stator Retention Clip Design
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Solution Overview
Problem
Current stator assembly retention methods in gas turbine engines are inefficient and prone to dislodgment, leading to potential energy loss and increased maintenance costs due to the lack of secure attachment of airfoils to shrouds.
Innovation Solution
The use of retention clips with an intermediate portion and elongated leg portions, formed from tempered metal or non-metallic materials, which are designed to securely fasten airfoils to inner and outer shrouds through a combination of arcuate and tapered features, enhancing stability and ease of assembly/disassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional retention methods are used to secure airfoils to shrouds, then the assembly process is simplified, but the retention is insufficient leading to dislodgment and energy loss
Solution Approach 1:
A retention clip serves as an intermediary component between the airfoil and the shroud, providing secure mechanical retention. The clip has a body that receives the airfoil and legs that engage with the shroud, acting as a mediator that transforms the connection from direct attachment to indirect secured attachment, thereby improving reliability without significantly complicating the overall assembly process.
2Reliability
If retention clips with complex features are used to prevent dislodgment, then retention security is improved, but manufacturing complexity increases
Solution Approach 1:
The retention clip is segmented into distinct functional portions: a body portion for receiving the airfoil and leg portions for engagement with the shroud. This segmentation allows each portion to be optimized for its specific function while maintaining manufacturability. The body can be formed with the airfoil receiving feature, and the legs can be formed with engagement features, enabling modular manufacturing approaches.
Solution Approach 2:
Different portions of the retention clip have different local qualities and geometries optimized for their specific functions. The body portion has a geometry optimized for receiving and securing the airfoil, while the leg portions have geometries optimized for engagement with the shroud. This local optimization allows each feature to perform its function effectively without requiring the entire component to be overly complex.
3Reliability
If secure attachment features are added to prevent airfoil dislodgment, then operational reliability is improved, but assembly time increases
Solution Approach 1:
The retention clip is pre-formed with its body and leg portions, including the airfoil receiving feature and shroud engagement features. This preliminary formation of the clip's geometry allows for rapid assembly, as the clip is ready to be installed and immediately provides secure retention without requiring complex assembly steps to create the retention features during the assembly process.
Data Source
Figure 1
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AI summary
A stator assembly (60) of a gas turbine engine includes a first shroud (62) extending about an axis to bound a flow path. The first shroud (62) defines a first shroud opening (68). An airfoil (66) has an airfoil body (66A) extending from a first end portion (66B). The first end portion (66B) is received in the first shroud opening (68) and defines at least one airfoil opening (66D). At least one retention clip (72) has an arcuate portion (72F) extending from a first elongated leg portion (72B). The first elongated leg portion (72B) and the arcuate portion (72F) are received through the at least one airfoil opening (66D) such that the at least one retention clip (72) limits movement of the airfoil (66) relative to the first shroud (62). A method of assembling a stator assembly (60) for a gas turbine engine comprises providing a shroud (62) defining a shroud opening (68); moving an end portion (66B) of an airfoil (66) into the shroud opening (68), the end portion (66B) defining at least one airfoil opening (66D); moving an arcuate portion (72F) of a retention clip (72) through the at least one airfoil opening (66D); and moving a first elongated leg portion (72B) of the retention clip (72) through the at least one airfoil opening (66D) such that the retention clip (72) limits movement of the airfoil (55A) relative to the shroud (62), the arcuate portion (72F) extending from an end of the first elongated leg portion (72B).