Cantilevered Vane J-Shaped Airfoil Vibration Stability
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Solution Overview
Problem
Contemporary gas turbine blades with shroud-type vanes exhibit low natural frequency, leading to vibration instability and increased rubbing, which affects the stability of the vane hub and efficiency of cooling.
Innovation Solution
A cantilevered vane with a J-shaped structure, featuring front-wing and rear-wing channels, exhaust connection channels, and protrusions to enhance cooling efficiency and turbulence, along with a rounded joint for improved stability, eliminates the need for a shroud structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a shroud-type vane with C-shaped structure is used, then the vane can be manufactured with standard geometry, but the natural frequency is low causing vibration instability and rubbing
Solution Approach 1:
The patent applies asymmetry by designing the airfoil cross-section with unequal acute angles at the vane hub and vane tip, replacing the symmetric C-shaped structure. This asymmetric geometry increases the natural frequency of the vane, thereby improving vibration stability and reducing rubbing while maintaining manufacturability
Solution Approach 2:
The patent inverts the conventional shroud-type structure by eliminating the shroud and adopting a cantilevered design where the airfoil extends directly from the vane hub. This structural inversion fundamentally changes the vibration characteristics and eliminates the low natural frequency issue associated with C-shaped shroud structures
2Temperature
If cooling channels are added to the airfoil, then cooling efficiency improves, but the structural complexity increases
Solution Approach 1:
The patent segments the cooling system into multiple independent channels including front-wing channels, rear-wing channels, and exhaust connection channels. This segmentation allows each channel to be optimized for specific cooling zones while maintaining overall system efficiency and manageable complexity
Solution Approach 2:
The patent applies local quality by providing different cooling channel configurations for different portions of the airfoil. The front-wing and rear-wing channels deliver cooling fluid to specific zones, and exhaust holes with varying diameters are positioned at different locations to optimize local cooling effectiveness
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
The cantilevered vane design stabilizes the vane hub, improves cooling efficiency, and adjusts cooling fluid flow rates through varying exhaust hole diameters, effectively reducing vibration and enhancing overall performance.
Implementation Method 1
a first channel (125) through which cooling fluid flows may be formed in the straight portion (123)
Implementation Method 2
a plurality of protrusions (136) formed in the rear-wing channel (128) to generate turbulence in a flow of the cooling fluid
Data Source
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AI summary
A cantilevered vane (100), for use with a rotary disc of a gas turbine, includes a root (110) supported in a dovetail slot formed in a circumferential surface of the rotary disc (10); and an airfoil protruding a predetermined height from the root and having a J-shaped cross-section throughout a front-wing portion and a rear-wing portion of the airfoil. The airfoil includes a straight portion (123) vertically extending upward from the root by a predetermined height; and a curved portion (124) integrally formed with an upper end of the straight portion to cantilever toward one side of the airfoil, the curved portion being inclined at a predetermined angle with respect to the straight portion. Cooling fluid flows through a first channel formed in the straight portion and a second channel formed in the curved portion. The first channel includes front-wing and rear-wing channels for guiding the cooling fluid to the front-wing and rear-wing portions.