Vane Segment Pin Mount and Anti-Rotation Stabilizer Rod
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Solution Overview
Problem
Implementing ceramic matrix composite (CMC) materials in gas turbine airfoils poses challenges due to unique structural and load distribution issues, particularly in preventing rotation and stress on the airfoil fairing, which existing designs fail to adequately address.
Innovation Solution
A vane arc segment design incorporating a pin mount and an anti-rotation stabilizer rod, where the stabilizer rod extends through the airfoil fairing and support platform, limits rotation of the support platform about the pin, thereby transferring aerodynamic loads to the spar instead of the airfoil fairing, and includes a spring for thermal expansion compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple pin mount is used for the support platform, then the device complexity is reduced, but the support platform rotates undesired under aerodynamic loads
Solution Approach 1:
A stabilizer rod is introduced as an intermediary element between the support platform and the spar. The stabilizer rod extends through the support platform and engages with the spar to prevent rotation, while the pin remains as the primary mounting element. This intermediary structure resolves the contradiction by adding minimal complexity to achieve rotational stability.
Solution Approach 2:
The mounting system is segmented into two functional components: the pin for primary mounting and the stabilizer rod for rotational stabilization. This segmentation allows each component to perform its specific function efficiently, with the pin handling mounting and the stabilizer rod preventing rotation, thereby reducing overall complexity while improving stability.
2Strength
If the airfoil fairing directly supports aerodynamic loads, then the structural integrity is maintained, but thermal expansion causes stress and deformation
Solution Approach 1:
The stabilizer rod acts as a mediator that transfers aerodynamic loads from the airfoil fairing to the spar, which is better positioned to handle these loads. This intermediary load path reduces thermal expansion stress on the airfoil fairing by distributing forces through the spar structure, thereby maintaining structural integrity while accommodating thermal effects.
Solution Approach 2:
The system accommodates thermal expansion by allowing the stabilizer rod and support platform to move relative to each other within the constraints of the pin mount. This parameter change approach enables the structure to expand and contract thermally without generating excessive stress, while still maintaining rotational stability.
3Ease of manufacture
If the support platform is freely mounted on the pin, then the ease of manufacture is improved, but the airfoil fairing experiences excessive stress under load
Solution Approach 1:
The stabilizer rod serves as an intermediary that redistributes stresses from the airfoil fairing to the spar. It maintains a simple pin mount for ease of manufacture while preventing the support platform from rotating and concentrating stress on the airfoil fairing. The stabilizer rod provides the necessary structural support without complicating the manufacturing process.
Solution Approach 2:
The mounting system is divided into the pin for simple installation and the stabilizer rod for stress distribution. This segmentation allows the support platform to be easily manufactured and installed on the pin while the stabilizer rod handles the stress management function, thereby maintaining ease of manufacture while reducing airfoil fairing stress.
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 effectively reduces stress on the airfoil fairing by preventing undesired rotation and accommodating thermal expansion differences, enhancing the structural integrity and operational stability of CMC airfoils in gas turbine engines.
Implementation Method 1
includes a spring for thermal expansion compensation
Data Source
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AI summary
A vane arc segment (60) includes an airfoil fairing (62) that has first and second fairing platforms (66, 68) and a hollow airfoil section (64)extending there between. There is a spar (72) having a spar platform (72a) adjacent the first fairing platform (66) and a spar leg (72b) that extends from the spar platform (72a) and through the hollow airfoil section (64). The spar leg (72b) has an end portion (74) with a clevis mount (76) that that protrudes from the second fairing platform (66). A support platform (78) adjacent the second fairing platform (66) has first and second through-holes (80a, 80b). The end portion (74) of the spar leg (72b) extends through the first through-hole (80a) and a pin (82) extends though the clevis mount (76) to lock the support platform (78) to the spar leg (72b). A stabilizer rod (84) extends through the second through-hole (80b) of the support platform (78) and limits rotation of the support platform (78) about the pin (82).