Turbomachine Blade Impact Damping Design

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Solution Overview

Problem

Existing turbomachine blade vibration damping systems, such as dissipative friction dampers, are ineffective in reducing blade vibrations, and alternative methods like impact contacts do not provide sufficient vibration reduction.

Innovation Solution

A blade design featuring matrices with strategically arranged impact chambers and impulse bodies, optimized by specific geometric and angular alignments, which utilize centrifugal force to achieve advantageous impact dynamics and reduce vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If dissipative friction dampers are used for blade vibration damping, then vibration reduction is attempted, but they are ineffective in reducing blade vibrations

Engineering Contradiction:
Improveblade vibrationVSAvoidvibration damping effectiveness
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent inverts the conventional friction-based dissipative damping approach by using impact-based detuning damping. Instead of relying on friction to dissipate vibration energy, the invention uses impact contacts between impulse bodies and the blade to detune vibration modes, fundamentally changing the damping mechanism from dissipation to detuning through impact forces.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the physical parameters of the damping system by introducing impulse bodies with specific masses (0.01-0.075g) and arranging them in impact chambers at specific locations and orientations on the blade. This changes the blade's vibration characteristics and natural frequencies to detune from excitation frequencies, thereby reducing vibrations.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If impact contacts are used for vibration reduction, then some vibration damping is achieved, but sufficient vibration reduction is not provided

Engineering Contradiction:
Improveblade vibrationVSAvoidvibration reduction sufficiency
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent segments the blade structure by introducing multiple discrete impact chambers containing individual impulse bodies. These are distributed at specific locations (leading edge, trailing edge, mid-span) and orientations on the blade, creating multiple independent impact zones that collectively provide sufficient vibration reduction through cumulative detuning effects.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs asymmetric arrangement of impact chambers with different orientations (60-120 degrees with rotation axis) and positions throughout the blade structure. This asymmetric distribution ensures that impact forces are applied in multiple directions and locations, providing comprehensive vibration reduction that overcomes the insufficiency of symmetric or single-location impact systems.

Inventive Principle:
Principle #4Asymmetry

3Object-affected harmful factors

If impulse bodies are arranged in impact chambers with freedom of movement, then impact dynamics are improved, but device complexity increases

Engineering Contradiction:
Improveshock dynamicsVSAvoidimpact chamber structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts the damping function from the blade's structural material by introducing separate, movable impulse bodies within dedicated impact chambers. This separation allows the impulse bodies to move independently and provide impact damping without complicating the blade's primary structural integrity, as the impulse bodies are contained within discrete chambers.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses small, simple impulse bodies (spherical or disk-shaped, 0.01-0.075g mass) that can be easily manufactured and replaced if needed. These simple geometric forms with freedom of movement provide effective impact dynamics without requiring complex mechanisms, balancing performance with制造 simplicity and low complexity.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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

The blade design effectively reduces vibrations by leveraging centrifugal force and precise arrangement of impact chambers and impulse bodies, providing improved shock dynamics and vibration control.

Implementation Method 1

Due to centrifugal force, impulse bodies can be particularly advantageous here

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3138996B1Turbomachine blade
Publication Date: 2019.12.11 MTU AERO ENGINES GMBH
  • EP3138996B1 patent drawingFigure 1
  • EP3138996B1 patent drawingFigure 2~4
  • EP3138996B1 patent drawingFigure 5~7

AI summary

The present invention relates to a blade for a turbomachine, in particular a compressor or turbine stage of a gas turbine, comprising at least one matrix with a first impact chamber (10) in which at least one impulse body (11) is arranged with movement clearance, at least one second impact chamber (20) whose center of volume is offset relative to a center of volume of the first impact chamber (10) along a first matrix axis (A) and in which at least one impulse body (21) is arranged with movement clearance, and at least one third impact chamber (30) whose center of volume is offset relative to the center of volume of the first impact chamber (10) along a second matrix axis (B) transverse to the first matrix axis (A) and in which at least one impulse body (31) is arranged with movement clearance, wherein the first matrix axis (A) forms an angle of at least 60° and at most 120° with a rotation axis (R) of the turbomachine.