Gas Turbine Stator Shroud Weight Reduction via Segmented Rubber Seals

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Solution Overview

Problem

Existing stator shrouds for gas turbine engines are heavy due to poured rubber inner air seals, which increase the overall weight of the engine.

Innovation Solution

A stator assembly with a shroud that includes a cavity with inserts and a rubber material to secure tab portions of vanes, providing an inner air seal while reducing weight through the use of pre-molded inserts and cavities, allowing for a lighter stator shroud with effective sealing and damping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If poured rubber inner air seals are used in stator shrouds, then vane damping and rotor to stator radial sealing are provided, but the overall weight of the engine increases

Engineering Contradiction:
Improvesealing capabilityVSAvoidengine weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The stator shroud is divided into multiple segments or sections, allowing the rubber material to be applied only in specific areas where sealing is required, rather than throughout the entire shroud structure. This segmentation reduces the total amount of rubber material needed, thereby reducing weight while maintaining sealing effectiveness at critical locations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The rubber material is applied locally only where sealing and damping are required, such as at the inner air seal regions and vane damping zones, rather than uniformly across the entire shroud. This localized application reduces material usage and weight while maintaining the necessary sealing and damping functions at specific critical areas.

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If poured rubber inner air seals are used in stator shrouds, then vane damping is provided, but the overall weight of the engine increases

Engineering Contradiction:
Improvevane dampingVSAvoidengine weight
Core Design Contradiction:
Stability of the object's compositionVSWeight of moving object

Solution Approach 1:

The damping function is segmented by applying rubber material only to specific regions where vibration damping is most needed, such as at the vane roots or along specific portions of the shroud, rather than throughout the entire structure. This targeted approach provides adequate damping while minimizing weight addition.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The rubber material is applied with varying properties or thicknesses in different locations to optimize damping performance where needed while reducing material in areas where damping is less critical, thereby achieving effective vibration control with reduced overall weight.

Inventive Principle:
Principle #3Local quality

3Reliability

If rubber material is used to secure tab portions of vanes to the shroud, then effective sealing and damping are achieved, but the weight of the stator shroud increases

Engineering Contradiction:
Improvesealing and damping performanceVSAvoidstator shroud weight
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The rubber material application is segmented into discrete zones corresponding to specific functional requirements - sealing zones near the rotor interface and damping zones near the vane attachments. This segmentation allows optimization of material distribution, reducing total weight while maintaining performance at each location.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the shroud receive rubber material with different properties or thicknesses tailored to their specific functions - thicker or more compliant material at sealing locations and thinner or stiffer material at damping locations - achieving optimal performance with minimized weight.

Inventive Principle:
Principle #3Local quality

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 solution results in a lighter stator shroud with improved sealing and damping capabilities, achieving weight savings and maintaining the engine's performance with minimal configuration changes.

Implementation Method 1

a rubber material disposed in the cavity of the shroud, the rubber material securing the tab portion of each of the plurality of vanes to the shroud

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

the rubber material may provide an inner air seal of the stator assembly

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3312386B1Shroud for gas turbine engine
Publication Date: 2019.11.27 UNITED TECH CORP
  • EP3312386B1 patent drawingFigure 1
  • EP3312386B1 patent drawingFigure 2~3
  • EP3312386B1 patent drawingFigure 4~5

AI summary

A stator assembly (70) for a stator of a gas turbine engine (20) is provided. The stator assembly having: a shroud (76) defining a cavity (94); a plurality of inserts (98) located within the cavity, each of the plurality of inserts defining a cavity (102); a plurality of vanes (74) secured to the shroud, wherein each of the plurality of vanes has a tab portion (84) located in the cavity of the shroud; and a rubber material (96) disposed in the cavity of the shroud, the rubber material securing the tab portion of each of the plurality of vanes to the shroud.