Polymeric Shroud Nesting Metallic Fitting for Gas Turbine Airfoils
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Solution Overview
Problem
Existing shrouded airfoils in gas turbine engines face challenges in material compatibility and efficiency due to the need for integrally formed metallic components, which can be costly and require significant machining, and lack effective sealing mechanisms.
Innovation Solution
The use of separate polymeric shrouds that nest into metallic fittings with complementary shapes, including a shelf and groove for seal members, allows for material diversity and efficient assembly, reducing material costs and weight while enhancing sealing through adhesive or mechanical fastening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If integrally formed metallic fittings and shrouds are used, then structural strength and reliability are improved, but manufacturing cost and complexity increase due to significant machining requirements
Solution Approach 1:
The airfoil is divided into separate components: a metallic airfoil body, a separate metallic fitting, and a separate polymeric shroud. This segmentation allows each component to be manufactured independently using optimized processes, reducing overall manufacturing complexity and cost while maintaining structural integrity through designed join interfaces.
Solution Approach 2:
The invention combines metallic materials (airfoil body and fitting) with polymeric materials (shroud) to create a composite structure. This allows each material to be selected for its optimal properties - metal for structural strength and polymer for weight reduction and cost-effective manufacturing - resolving the contradiction between strength and manufacturing ease.
2Stability of the object's composition
If integrally formed metallic fittings and shrouds are used, then structural integrity is improved, but manufacturing time and productivity decrease due to significant machining requirements
Solution Approach 1:
By segmenting the airfoil into separately manufacturable components (airfoil body, fitting, and shroud), each component can be produced independently using faster, less complex processes. The assembly of these pre-manufactured parts significantly reduces total manufacturing time compared to creating a single integral component through extensive machining.
Solution Approach 2:
The fitting and shroud are prepared in advance with pre-formed features (such as recesses and attachment interfaces) that facilitate rapid assembly. This preliminary preparation of components eliminates the need for time-consuming final machining operations on the assembled structure.
3Weight of moving object
If separate polymeric shrouds are used instead of integrally formed metallic components, then weight is reduced and material costs decrease, but structural strength and reliability may be compromised
Solution Approach 1:
The invention uses a composite construction where metallic components (airfoil body and fitting) provide the primary structural strength and load-bearing capacity, while the polymeric shroud provides protective and functional features. This composite approach achieves weight reduction while maintaining structural reliability through proper material selection and interface design.
Solution Approach 2:
Different materials are applied to different parts of the structure based on local requirements: metallic materials with high strength-to-weight ratios are used where structural strength is critical (airfoil body and fitting), while polymeric materials are used for the shroud where weight reduction and cost reduction are priorities but extreme structural loads are not present.
4Adaptability or versatility
If separate polymeric shrouds are used instead of integrally formed components, then material diversity and ease of assembly are improved, but manufacturing precision and alignment may be compromised
Solution Approach 1:
The polymeric shroud is designed to nest within or around the metallic fitting, with complementary geometric features that guide precise alignment during assembly. This nested configuration inherently provides alignment tolerance and ensures proper positioning without requiring extremely tight manufacturing tolerances on individual components.
Solution Approach 2:
The interface between the polymeric shroud and metallic fitting is designed with equipotential geometric features (such as matching contours and engagement surfaces) that naturally align the components during assembly, reducing the impact of variations in manufacturing precision and ensuring consistent alignment across all assembled units.
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 enables weight reduction, cost-effective production, and improved sealing in gas turbine engines by using polymeric shrouds with metallic fittings, enhancing the structural integrity and operational efficiency of airfoils.
Implementation Method 1
A fitting includes a body portion, a fillet portion, and a neck portion joining the body portion and the fillet portion. The neck portion includes a shelf, and here is a fastener through the airfoil body. A shroud has a complementary shape to the shelf such that the shroud nests in the shelf.
Data Source
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, a fitting located at one of the first end or the second end, the fitting including a body portion, a fillet portion, and a neck portion joining the body portion and the neck portion, the neck portion including a shelf, a fastener through the airfoil body, and a shroud having a complementary shape to the shelf such that the shroud nests in the shelf.