Turbo-machine Stator Vane Mistuning via Relief Slits
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Solution Overview
Problem
Gas turbine engine stator segments with clustered vanes exhibit similar vibratory modes leading to resonance and mistuning, which can shorten the lifespan of the segments due to destructive harmonious vibratory modes.
Innovation Solution
The stator segments are designed with radially extending vanes and relief slits of varying widths and depths, filled with damping materials, to create discordant resonant frequencies and minimize damage, with the slit configuration determined to deliberately mistune each vane's vibratory mode to prevent destructive resonance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If stator segments have clustered vanes with uniform configuration, then manufacturing is simplified, but destructive resonance occurs due to similar vibratory modes
Solution Approach 1:
The patent applies local quality by making each vane cluster unique through varying the number of vanes (5-9 vanes per cluster), differentiating platform widths, and varying relief slit configurations. This ensures that while the overall clustered structure simplifies manufacturing compared to individual vanes, each cluster has distinct local characteristics that prevent resonant coupling and extend component life.
2Strength
If relief slits are added to isolate vanes from vibration modes, then vane cracking is prevented, but stress relief complexity increases
Solution Approach 1:
The patent applies segmentation by dividing each vane into multiple segments using relief slits that extend partially through the vane thickness. These slits create isolated segments within each vane that can move independently, preventing stress buildup and cracking while maintaining the overall structural integrity and reducing the need for additional complex damping mechanisms.
3Reliability
If damping materials are placed in relief slits, then vibratory mode isolation is enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent merges multiple functions into the relief slits: they provide stress relief, vibration isolation, and damping material containment. The damping materials are integrated directly into the relief slit structures, eliminating the need for separate damping components and simplifying assembly. This combined approach enhances vibration amplitude reduction while maintaining ease of manufacture through a unified structural solution.
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 configuration effectively extends the lifespan of the stator segments by reducing destructive vibratory modes and preventing resonance, thereby enhancing the durability and operational reliability of the gas turbine engine.
Implementation Method 1
The stator segment also includes a damper to reduce vibration amplitudes, thereby helping prevent vane cracking
Implementation Method 2
These relief slits also help isolate vanes from vibration modes of adjacent vanes
Data Source
Figure 1
Figure 2~4
AI summary
A stator (56) for a turbo-machine and a method for creating the stator (56). The stator (56) has a plurality of airfoils (50) extending radially therefrom and comprises a base (75) from which the airfoils (50) extend, and slits (125) disposed in the base (75). Each slit (125) is disposed adjacent a pair of airfoils (50). A distance (W1) between a first set of adjacent slits (125) and a distance (W2) between a second set of adjacent slits (125) varies.