Hybrid Metal Composite Spool for Gas Turbine Engines
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Solution Overview
Problem
Rotating machinery spools, particularly in gas turbine engines, face challenges in achieving a balance between being lightweight, strong, and robust due to the limitations of composite materials in terms of tribological performance and inherent strength compared to metallic materials.
Innovation Solution
A hybrid metal and composite spool design is introduced, featuring metal rings on the outer diameter or surface of a composite spool shell with features like dovetail slots and seal tooth rings, bonded using a shrink bonded joint and annular adhesive layers, allowing for enhanced strength and robustness while maintaining weight reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If composite materials are used for spools, then weight is reduced, but tribological performance and inherent strength deteriorate
Solution Approach 1:
The invention uses a hybrid composite structure combining metal rings with composite spool shell. The metal rings provide robust tribological performance and inherent strength, while the composite shell maintains weight reduction benefits. This composite approach resolves the contradiction by integrating materials with complementary properties.
Solution Approach 2:
The invention applies metal rings at specific locations (outer diameter or outer surface) of the composite spool shell where tribological performance and strength are most needed. This local application of metal material provides enhanced performance only where required, while maintaining overall weight reduction.
2Weight of moving object
If composite materials are used for spools, then weight is reduced, but structural integrity under large forces deteriorates
Solution Approach 1:
The hybrid metal-composite structure provides both weight reduction and structural integrity. The metal rings reinforce the composite shell to withstand large forces including hoop stress and radial forces, while maintaining the weight advantages of composite materials.
Solution Approach 2:
Metal rings are strategically positioned on the composite spool shell to provide localized reinforcement where structural integrity is most critical under operational forces, while the majority of the spool remains lightweight composite material.
3Reliability
If metal rings are added to composite spool, then strength and tribological performance improve, but device complexity increases
Solution Approach 1:
The spool is divided into distinct segments: metal rings and composite spool shell. This segmentation allows each component to be optimized independently and assembled through bonding, simplifying manufacturing while achieving the desired performance characteristics.
Solution Approach 2:
The invention merges metal rings with composite spool shell through bonding to create a unified hybrid structure. This combination integrates the advantages of both materials into a single functional component, achieving improved performance without excessive complexity.
4Strength
If metal rings are added to composite spool, then structural integrity improves, but manufacturing complexity increases
Solution Approach 1:
The spool is manufactured in separate segments (metal rings and composite shell) that can be produced using optimized processes for each material type, then assembled through bonding. This segmentation simplifies manufacturing by allowing specialized processes for each component.
Solution Approach 2:
Metal rings are positioned on the uncured composite spool shell before curing, allowing the adhesive to bond the components together during the curing process. This preliminary positioning simplifies assembly and ensures proper alignment.
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 hybrid spool design effectively combines the strength and stiffness of composite materials with the robustness of metal, providing improved tribological performance and structural integrity under various operational forces, enhancing the overall performance of gas turbine engines.
Implementation Method 1
One or more annular adhesive layers may be between the one or more metal rings and the composite spool shell. A shrink bonded joint including the annular adhesive layers may be between the one or more metal rings and the composite spool shell.
Implementation Method 2
heating the one or more metal rings to a temperature at least sufficient to slide the rings over a cured composite spool shell, sliding the heated one or more metal rings in place on an outer surface of the cured composite spool shell of the spool, and allowing the one or more metal rings to cool and shrink onto the cured shell
Data Source
AI summary
A hybrid metal and composite spool includes metal rings on an outer diameter of a composite spool shell. Metal rings may include features such as annular or axial dovetail slots. Adhesive layers may be between the metal rings and composite shell which may be connected by a shrink bonded joint. The metal rings may include a single seal tooth ring with an annular radially extending seal tooth. A method for fabricating the spool may include fabricating one or more metal rings with the features therein, positioning the metal rings in place on an outer surface of an uncured composite spool shell of the spool before curing the shell, and curing the shell with the one or more metal rings positioned in place. Alternatively, rings may be heated to a temperature at least sufficient to slide rings over a cured composite shell, and allowed to cool and shrink onto shell.