Abradable Seal Structure Using Laser-Deposited Superalloy Cells
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Solution Overview
Problem
Abradable sealing elements in gas turbine engines face challenges in maintaining mechanical, thermophysical, and tribological properties, leading to reduced usable lifespan and increased maintenance needs due to excessive wear and cracking issues.
Innovation Solution
The use of additive-layer, powder-fed, laser-weld deposition to form nickel-based superalloy wall structures within abradable sealing elements, where the nickel-based superalloy constitutes 10% to 50% of the total volume, enhancing mechanical and thermophysical properties and reducing residual stresses and cracking tendencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional machining or deposition methods are used to form sealing element walls, then manufacturing capability is achieved, but mechanical strength and resistance to cracking are insufficient
Solution Approach 1:
The sealing element employs a composite structure where a nickel-based superalloy substrate provides mechanical strength and crack resistance, while an abradable material filling the cells provides sealing functionality. This composite approach allows each material to contribute its superior properties, resolving the contradiction between structural integrity and sealing performance
Solution Approach 2:
The nickel-based superalloy walls are strategically positioned to provide localized structural support and crack resistance where needed, while the abradable material occupies the cell spaces to provide localized sealing contact with blade tips. This spatial differentiation of material properties resolves the contradiction by assigning each material to its optimal functional zone
2Reliability
If abradable material is used for sealing, then sealing performance is improved, but mechanical properties and thermophysical stability deteriorate
Solution Approach 1:
The sealing element uses a composite design where the nickel-based superalloy substrate provides superior mechanical properties and thermophysical stability, while the abradable material confined within cells delivers sealing performance. This resolves the contradiction by having each material perform its specialized function in a composite structure
Solution Approach 2:
The abradable material is localized within enclosed cells formed by the superalloy walls, providing sealing contact only where blade tips interact with the cell openings. The superalloy walls provide structural support throughout the entire component, resolving the contradiction by spatially separating sealing and structural functions
3Strength
If wall structure volume is increased to improve mechanical properties, then strength improves, but the proportion of abradable material decreases reducing sealing effectiveness
Solution Approach 1:
The design optimizes the local distribution of materials: nickel-based superalloy walls occupy approximately 30-70% of total volume to provide structural strength, while abradable material fills the remaining cell spaces to ensure sealing effectiveness. This balanced volumetric distribution resolves the contradiction between structural and sealing requirements
Solution Approach 2:
The composite structure allows the superalloy substrate to contribute mechanical strength proportional to its volume fraction, while the abradable filling material contributes sealing performance. The synergistic combination in a composite architecture resolves the contradiction by allowing both materials to function at optimal volumes
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 approach results in abradable sealing elements with improved mechanical, thermophysical, and tribological properties, extending their usable lifespan and reducing maintenance requirements by minimizing cracking and wear, while allowing for tailored designs suitable for specific applications.
Implementation Method 1
melting the powdered material, as well as a portion of the substrate, by way of a laser beam to form a weld pool
Implementation Method 2
additive-layer, powder-fed, laser-weld deposition onto the substrate
Data Source
AI summary
An abradable sealing element comprises a substrate and a sealing structure. The sealing structure comprises one or more wall structures extending from the substrate and defining at least one open cell which is filled with abradable material. The one or more wall structures are formed by additive-layer, powder-fed, laser-weld deposition onto the substrate. The one or more wall structures are formed from nickel-based superalloy and constitute from about 10% to about 50% of the total volume of the sealing structure.