Guide Vane Segment Stiffening for Gas Turbine Vibration Damping
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Solution Overview
Problem
Existing guide vane segments in gas turbines, particularly in aircraft engines, face challenges in effectively reducing dynamic loads and vibrations, leading to component fatigue and reduced service life.
Innovation Solution
The guide vane segment incorporates stiffening elements that extend radially and are designed with a contour based on the guide vane projections, with a width of up to 20% of the projection's thickness, forming a common stiffening structure with connecting elements to reduce dynamic loads and enhance damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional stiffening elements are added to the cover band, then structural strength is improved, but dynamic load reduction is insufficient
Solution Approach 1:
The stiffening elements are designed with varying cross-sectional areas along their length, with larger cross-sections near the guide vane roots where stresses are highest, and tapering towards the free end. This local variation in stiffness provides optimal dynamic load reduction where needed most, while avoiding unnecessary weight and material in regions where less stiffening is required.
Solution Approach 2:
The stiffening elements extend in the radial direction from the cover band outer surface, creating a three-dimensional stiffening structure that adds structural strength without interfering with the two-dimensional flow path. This radial extension allows the stiffening elements to form an extension of the guide vanes, effectively increasing the guide vane span and improving dynamic load reduction.
2Strength
If stiffening elements with larger cross-section are used, then structural strength is improved, but material usage increases
Solution Approach 1:
The stiffening elements feature a non-uniform cross-sectional area that varies along their length, with maximum cross-section at the rooted end and tapering towards the free end. This localized concentration of material where stresses are highest provides optimal strength-to-material-ratio, avoiding unnecessary material usage in regions where less stiffening is required.
Solution Approach 2:
The stiffening elements are designed to provide just sufficient stiffness to reduce dynamic loads to acceptable levels, rather than over-engineering with excessive material. The cross-sectional dimensions are optimized to achieve the minimum required structural strength while minimizing material consumption.
3Reliability
If multiple stiffening elements are added to each cover band, then vibration damping is improved, but device complexity increases
Solution Approach 1:
The guide vane segment is divided into multiple individual stiffening elements distributed around the cover band perimeter, with each element serving as an independent vibration damping component. This segmentation allows each stiffening element to effectively damp local vibrations in its vicinity, providing comprehensive vibration control throughout the guide vane segment.
Solution Approach 2:
Multiple stiffening elements are integrated into a unified design where each element follows the same geometric pattern and attachment methodology. This merging of design approaches simplifies manufacturing and assembly, as the same stiffening element design can be replicated around the entire cover band, reducing overall device complexity despite the presence of multiple elements.
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 significantly reduces dynamic loads, thereby increasing the service life of the guide vane segment by effectively damping vibrations and minimizing material usage while maintaining structural integrity.
Implementation Method 1
the stiffening elements can be used to damp vibrations on a cover band of a guide vane segment
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to a guide vane segment (10) for a gas turbine, in particular an aircraft engine (1), comprising a plurality of guide vanes (20), a radially outer cover band (30) connecting the plurality of guide vanes (20), wherein stiffening elements (40) integral to and/or integrated into the cover band (30) are arranged on a radial outer surface (31) of the cover band (30).In order to better reduce dynamic loads during the operation of the gas turbine, it is proposed that the stiffening elements (40) form an extension of the guide vanes (20) in the radial direction (R), and/or that a contour of the stiffening elements (40) on the outside (31) of the shroud (30) lies within an outer contour (A) formed by a band (B) around a projection (P) of outlines (21) of the guide vane (20) on a radial inside (32) onto the outside (31) of the shroud (30), wherein a width (b) of the band (B) in the circumferential direction (U) around the projection is at most 20% of the thickness (d) of the projection (P) in the circumferential direction (U).