Shrouded Turbine Blade Cut Corner Vibration Control

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Solution Overview

Problem

Turbine blades in gas turbine engines experience damaging vibration characteristics, leading to reduced lifespan and potential engine failure due to undesirable vibration modes.

Innovation Solution

A shrouded turbine blade design with strategically cut corners on the outer shroud to alter vibration mode shapes, eliminating anti-nodes that cause damage, using analytical or experimental methods to determine and modify the blade's shape to reduce vibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If turbine blades are designed with complete outer shrouds, then structural integrity and sealing are improved, but damaging vibration characteristics and anti-node formation occur

Engineering Contradiction:
Improvestructural integrityVSAvoidvibration resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent removes specific portions (corners) from the outer shroud of the turbine blade to eliminate anti-nodes that cause damaging vibrations. This extraction of problematic regions maintains the overall structural integrity while eliminating the harmful vibration characteristics.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies local modification by cutting corners only at specific locations where anti-nodes form, rather than modifying the entire shroud. This localized approach targets the specific vibration problem areas while preserving the structural integrity of the remaining shroud portions.

Inventive Principle:
Principle #3Local quality

2Reliability

If turbine blade corners are cut to eliminate anti-nodes, then vibration characteristics are improved, but manufacturing complexity increases

Engineering Contradiction:
Improvevibration resistanceVSAvoidblade manufacturing
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent incorporates the corner cuts as part of the initial blade manufacturing process, performing the vibration-mitigating modification beforehand rather than requiring separate post-manufacturing steps. This integrates the vibration control feature into the standard manufacturing workflow.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2938832B1Shrouded turbine blade with cut corner
Publication Date: 2019.02.06 UNITED TECH CORP
  • EP2938832B1 patent drawingFigure 1
  • EP2938832B1 patent drawingFigure 2
  • EP2938832B1 patent drawingFigure 3

AI summary

A method includes determining a vibration characteristic of a shrouded turbine blade, which includes an airfoil attached to a shroud. A corner of the shrouded turbine blade can be removed after determining the vibration characteristic.