Compressor Guide Vane Damping Inserts for Turbomachine Vibration

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Solution Overview

Problem

Modern turbomachines face high dynamic stresses due to reduced stages and parts, leading to increased load on each stage and diminished damping effects, particularly with brazing technologies that reduce vibrational energy dissipation.

Innovation Solution

The introduction of damping inserts with viscoelastic layers sandwiched between metal layers, positioned in housings perpendicular to radial cuts, providing varying geometries such as H-shaped, X-shaped, and preloaded configurations to enhance damping and reduce vibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the number of stages is reduced to maintain performance, then productivity is improved, but dynamic stresses on each stage increase and damping effect decreases

Engineering Contradiction:

ImproveperformanceVSAvoiddynamic stresses

Core Design Contradiction:

ProductivityVSStress or pressure

Solution Approach 1:

The patent changes the material parameter of the connecting elements from rigid (metal) to viscoelastic, which fundamentally alters the damping characteristics. This allows the system to maintain performance with fewer stages while the viscoelastic material absorbs and dissipates the increased dynamic stresses through hysteresis losses.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite construction by combining metal layers with viscoelastic damping inserts to create connecting elements that possess both structural strength and vibration damping capabilities. This composite approach enables the reduction of stage count while managing the increased dynamic loads through the damping properties of the viscoelastic material.

Inventive Principle:

Principle #40Composite materials

2Device complexity

If brazing is used to eliminate connections, then device complexity is reduced, but vibrational energy dissipation decreases

Engineering Contradiction:

Improvenumber of connectionsVSAvoidvibrational energy dissipation

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The patent introduces viscoelastic damping inserts as intermediary elements between the inner and outer rings, replacing the need for brazed connections. These inserts act as mediators that provide both mechanical connection and vibration damping, eliminating the energy loss associated with rigid brazed joints while maintaining structural integrity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the connection method from rigid brazing to viscoelastic damping inserts, which fundamentally alters the energy dissipation mechanism. The viscoelastic material provides continuous damping through hysteresis, converting vibrational energy into heat, thereby preventing the energy loss problem of brazed connections.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If individual vanes are used instead of one-piece construction, then adaptability is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvevane configurationVSAvoidnumber of parts

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the outer ring into multiple elementary sectors separated by radial cuts, allowing individual blade adjustment and optimization. This segmentation enables adaptability in vane configuration while the modular design with standardized damping inserts keeps the overall assembly process manageable.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent creates universality by using standardized damping inserts that can be applied to multiple connection points across the sector. These inserts serve multiple functions (connection, damping, vibration reduction) and can be used throughout the assembly, simplifying manufacturing despite the segmented vane structure.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution significantly reduces system vibration levels by introducing nonlinear stiffness, disrupting resonance modes and stabilizing natural frequencies through continuous variation in local stiffness, thereby mitigating the adverse effects of high dynamic stresses.

Implementation Method 1

the inserts consist of at least one viscoelastic layer, each viscoelastic layer being sandwiched between two metal layers

Methodology Applied

Scientific EffectViscoelasticity: Viscoelasticity

Implementation Method 2

damping inserts being positioned in said housings... providing varying geometries... to enhance damping and reduce vibration

Methodology Applied

Scientific EffectHysteresis damping: Hysteresis

Implementation Method 3

Methodology Applied

Scientific EffectNonlinear stiffness:

Data Source

PatentUS7887286B2Sector of a compressor guide vanes assembly or a sector of a turbomachine nozzle assembly

Publication Date: 2011.02.15 SAFRAN AIRCRAFT ENGINES SAS

AI summary

A sector of a compressor guide vanes assembly or a sector of a turbomachine nozzle assembly. It comprises an inner ring sector (4), an outer ring sector (6) and a multitude of blades (8) connecting the inner ring sector (4) to the outer ring sector (6). The outer ring sector (6) or the inner ring sector (4) comprises radial cuts (10) situated between two consecutive blades (8) in such a way as to split them into the same number of elementary sectors as there are blades. Housings (14) are provided, secant to the radial cuts (10), damping inserts (16) being positioned in said housings.