Variable Guide Vane Assembly Closed-Ended Slot Design
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Solution Overview
Problem
Existing variable guide vane assemblies in gas turbine engines face issues with maintaining contact between vane arms and sliders during rotational motion, leading to potential disengagement and performance interruptions in the gaspath.
Innovation Solution
The design incorporates vane arms with closed-ended slots that trap sliders, ensuring continuous contact by using a peripheral wall with guiding walls and an end wall that prevents sliders from exiting, and employing composite materials for increased structural stiffness and reduced wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If open-ended slots are used in vane arms, then the structure is simpler and easier to manufacture, but sliders may disengage during rotational motion causing performance interruptions
Solution Approach 1:
The slot structure is segmented into multiple functional sections: a main slot portion for slider movement, guiding walls for lateral constraint, and an end wall forming a closed end. This segmentation allows each section to perform its specific function while collectively ensuring reliable slider retention throughout the rotational cycle
Solution Approach 2:
Instead of relying on external retention mechanisms or complex interlocking features, the design inverts the approach by making the slot itself self-contained and closed at one end. This inverted thinking transforms the slot from a simple opening into a self-retaining structure that passively prevents slider disengagement through its geometry
2Strength
If composite materials are used for vane arms, then structural stiffness and wear resistance are improved, but manufacturing complexity and cost increase
Solution Approach 1:
The vane arms are constructed using composite materials that combine the structural benefits of multiple materials, providing enhanced stiffness and wear resistance. The composite structure allows optimization of mechanical properties while managing the complexities of manufacturing through integrated design considerations
3Reliability
If fully enclosed slots with guiding walls are used, then slider retention and rotational constraint are improved, but manufacturing precision requirements increase
Solution Approach 1:
The guiding walls and end wall are designed with specific local geometric features that provide precise constraint where needed. The guiding walls have controlled dimensions and orientations to ensure proper slider retention, while the end wall provides a definitive stop. This localized precision approach concentrates manufacturing requirements at critical locations rather than throughout the entire structure
Data Source
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Figure 3
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AI summary
A variable guide vane (VGV) assembly (40) for a gas turbine engine has: vanes (42) distributed about a central axis and having airfoils (42a) between stems (42f) at respective ends of the airfoils; a unison ring (44); sliders (50) protruding from the unison ring; and vane arms (52) engaged to first stems and defining respective slots (S), each of the slots extending in a direction having a radial component relative to a respective one of the spanwise axes (A), the sliders received within respective ones of the slots, a slot extending from a proximal end (52d) to a distal end (52e) along a slot axis, the vane arm defining the slot having an end wall (52i)at the distal end, the end wall extending in a direction having a component transverse to the slot axis such that a slider abuts against the end wall when the slider is at the distal end to prevent the sliders from moving out of the slots.