Polymeric Shroud Bonded to Metallic Airfoil Fitting

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Solution Overview

Problem

Conventional shrouded airfoils in gas turbine engines face challenges in material compatibility and efficiency due to the need for integrally formed metallic shrouds and fittings, which are costly and require significant machining, limiting material options and geometric flexibility.

Innovation Solution

The use of polymeric shrouds, which can be separately formed and assembled around metallic fittings, allowing for different material choices and easier geometric configuration, along with the integration of seal members for enhanced sealing and assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If integrally formed metallic shrouds and fittings are used, then structural integrity is ensured, but manufacturing cost increases and material flexibility decreases

Engineering Contradiction:
Improvestructural integrityVSAvoidmanufacturing cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The airfoil assembly is divided into separate components: a metallic fitting and a polymeric shroud, which are assembled together rather than formed as a single integral piece. This segmentation allows each component to be manufactured independently using optimal processes for each material, reducing overall manufacturing cost and complexity while maintaining structural integrity through the assembled connection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention employs a composite structure combining metallic fitting material with polymeric shroud material. This composite approach leverages the strengths of both materials - the metallic fitting provides structural strength and rigidity, while the polymeric shroud provides sealing and corrosion resistance, achieving optimal performance at lower cost than all-metallic integral construction.

Inventive Principle:
Principle #40Composite materials

2Strength

If integrally formed metallic shrouds are used, then structural integrity is ensured, but manufacturing complexity increases due to significant machining requirements

Engineering Contradiction:
Improvestructural integrityVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

By segmenting the airfoil assembly into separate metallic fitting and polymeric shroud components, the manufacturing process is simplified. Each component can be manufactured using less complex processes appropriate to its material and function, avoiding the significant machining operations required for integral metallic shrouds while maintaining structural integrity through the assembled configuration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The polymeric shroud acts as an intermediary component between the metallic fitting and the gas path environment. This intermediary element provides sealing and protective functions that would otherwise require complex machining of the metallic fitting, thereby reducing manufacturing complexity while maintaining structural and functional integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If integrally formed metallic shrouds are used, then structural integrity is ensured, but material flexibility decreases

Engineering Contradiction:
Improvestructural integrityVSAvoidmaterial flexibility
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The composite structure combining metallic and polymeric materials provides material flexibility by allowing selection of optimal materials for each component's specific requirements. The metallic fitting provides structural strength, while the polymeric shroud provides corrosion resistance and sealing capabilities, enabling adaptation to different service conditions and design requirements.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Segmenting the airfoil assembly into separate metallic and polymeric components enables independent material selection and optimization for each part. This segmentation provides versatility in material choice, allowing engineers to select from a broader range of materials with different properties to meet specific performance, environmental, and cost requirements for different applications.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2861849B1Airfoil, corresponding turbine engine and method of assembling an airfoil
Publication Date: 2019.12.11 UNITED TECH CORP
  • EP2861849B1 patent drawingFigure 1~2
  • EP2861849B1 patent drawingFigure 3~6
  • EP2861849B1 patent drawingFigure 7~9

AI summary

An airfoil includes an airfoil body that extends between a leading edge and a trailing edge, a suction side and a pressure side, and a first end and a second end. At least one fitting is located on at least one of the first end and the second end. The fitting includes at least one mounting lug. At least one shroud is adhesively bonded to the at least one fitting.