Turbine Guide Vane Bulge Design for Vibration Control
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Solution Overview
Problem
Conventional turbine engine guide vanes experience excessive vibration amplitudes due to eigenfrequency coincidences with urging frequencies during operation, particularly in the first stripe vibration mode, leading to potential deterioration or breakage.
Innovation Solution
A guide vane design featuring a succession of five bulge portions along the tangential direction, with alternating convexity, and a specific stacking law for the center of gravity's tangential coordinate, which shifts the eigenfrequency away from urging frequencies, reducing vibration amplitudes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional guide vane geometry is used, then the manufacturing is simple, but the eigenfrequency coincides with urging frequencies causing large vibration amplitudes
Solution Approach 1:
The invention applies curvature modifications to the guide vane geometry through five bulge portions with alternating convexity along the tangential direction. These curved geometric features shift the eigenfrequency of the vane in the first stripe vibration mode away from the urging frequencies generated by rotor rotation, thereby reducing vibration amplitudes and preventing damage while maintaining a manufacturable design.
2Reliability
If the eigenfrequency is shifted away from urging frequencies, then vibration amplitudes are reduced, but the vane geometry becomes more complex
Solution Approach 1:
The invention implements local quality modifications by introducing five specific bulge portions at predetermined locations along the tangential direction of the guide vane. Each bulge portion has alternating convexity (first convex, second concave, third convex, fourth concave, fifth convex), creating localized geometric variations that collectively shift the eigenfrequency without requiring complete redesign of the entire vane structure.
3Reliability
If a single bulge portion is used to modify vibration, then the geometry is simple, but the eigenfrequency shift is insufficient for stripe modes
Solution Approach 1:
The invention segments the vibration modification function into five distinct bulge portions distributed along the tangential direction of the guide vane. This segmentation allows each bulge portion to contribute to the overall eigenfrequency shift, achieving sufficient separation from urging frequencies for stripe modes, which require more distributed geometric modifications compared to other vibration modes.
Data Source
AI summary
The present invention relates to a turbine engine guide (23) vane (25), with a height (H) extending between a vane root (26) and a vane tip (27) along a radial direction (Z), said vane (25) comprising a succession of five bulge portions along a tangential direction (Y) perpendicular to the radial direction (Z), this succession of bulge portions extending over the whole height (H) of the vane (25), and the convexity of the successive bulge portions being alternately in one direction and in the other. The vane (25) has the advantage of having an eigenfrequency for the first striped vibration mode which is different from the urging frequencies of said vane (25), during the operation of the turbine engine.