Modified J-Type Cantilevered Vane for Gas Turbine
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Solution Overview
Problem
Conventional gas turbine blades with C-shaped bowed vanes suffer from reduced natural frequency, leading to a risk of flutter and inadequate vibration stability and fluidity.
Innovation Solution
A modified J-type cantilevered vane with a root attachment and an airfoil featuring a linear part and a curved part, biased in the circumferential direction, along with a rounded structure at the junction, and passages for cooling fluid to enhance stability and fluidity, is introduced.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a C-shaped bowed vane is used, then the structure is simple and easy to manufacture, but the natural frequency is reduced leading to flutter risk and poor vibration stability
Solution Approach 1:
The patent applies asymmetry by transitioning from a symmetric C-shaped vane to an asymmetric J-type vane configuration. The J-type shape features a straight leading edge portion and a curved trailing edge portion, creating asymmetric geometry that increases the natural frequency of the airfoil while maintaining manufacturing feasibility. This asymmetric design prevents flutter by altering the vibrational characteristics of the blade.
Solution Approach 2:
The patent incorporates curvature principles by designing the trailing edge portion of the airfoil with a curved configuration rather than a straight line. The curved trailing edge portion extends in a direction inclined relative to the leading edge, creating a J-shaped profile that enhances structural stiffness and natural frequency while maintaining aerodynamic efficiency and manufacturability.
2Device complexity
If a C-shaped bowed vane is used, then the structure is simple, but the fluidity of fluid is insufficient
Solution Approach 1:
The curved trailing edge portion of the J-type airfoil improves fluidity by creating a smoother flow path for the gas. The curved configuration reduces flow separation and turbulence compared to a straight-edged design, enhancing the aerodynamic performance and productivity of the gas turbine while adding minimal structural complexity.
3Reliability
If the linear part and curved part are biased in the circumferential direction, then the vibration stability is enhanced, but the manufacturing precision requirements increase
Solution Approach 1:
The biased configuration of the linear and curved parts creates an asymmetric J-type profile that enhances vibration stability. The asymmetry in the circumferential direction positioning of these parts optimizes the natural frequency and flutter resistance, though it does require precise manufacturing to achieve the intended geometric configuration.
Data Source
AI summary
A modified J-type cantilevered vane reduces rubbing of an airfoil and enhances the vibration stability of a vane hub and the fluidity of fluid. The cantilevered vane includes a root attachment inserted into a slot formed in an inner circumferential surface of a casing of a gas turbine, and an airfoil vertically extending from the root attachment to a predetermined height. The airfoil includes a linear part extending in a radial direction from the inner circumferential surface of the casing toward a rotating shaft of the gas turbine, and a curved part integrally formed with the linear part, the curved part including a bend beginning from one end of the linear part and curving in a circumferential direction of the rotating shaft. Overall, the linear part and the curved part are biased in the circumferential direction, since the airfoil has a J-shaped X-axis profile and a C-shaped Y-axis profile.