Hybrid Blade Outer Air Seal with Ceramic Inserts
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Solution Overview
Problem
Gas turbine engine Blade Outer Air Seal (BOAS) segments face challenges in thermal management and durability due to high temperatures and mechanical mismatch between metal alloys and ceramic materials, leading to inefficiencies and reduced component life.
Innovation Solution
A BOAS assembly featuring a metal alloy body with non-metallic ceramic inserts flush with the surface, an intermediate bonding layer, and a graded ceramic-metal transition to accommodate thermal and mechanical property mismatches, along with an abradable thermal barrier coating for enhanced durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal alloy BOAS segments are used, then structural strength is maintained, but thermal management efficiency deteriorates due to high heat conduction requiring excessive cooling flow
Solution Approach 1:
The BOAS segment employs a composite structure combining metal alloy substrate with ceramic coating layers. The metal alloy provides structural strength and mechanical properties, while the ceramic coating (such as thermal barrier coating or abradable thermal barrier coating) provides thermal insulation properties. This composite approach reduces heat conduction to the cooling air, thereby reducing cooling flow requirements while maintaining structural integrity.
2Use of energy by moving object
If ceramic inserts are added to improve thermal insulation, then cooling flow requirements reduce, but device complexity increases due to additional bonding layers and manufacturing steps
Solution Approach 1:
Instead of using discrete ceramic inserts requiring bonding layers, the patent applies ceramic coating directly onto the metal alloy surface. This creates a localized thermal insulation layer exactly where needed (on the surface exposed to hot gas) without requiring complex assembly of separate ceramic components. The coating process integrates seamlessly with the existing manufacturing workflow.
Solution Approach 2:
The patent removes the intermediate bonding layer that would be required if discrete ceramic inserts were used. By applying ceramic coating directly to the metal alloy surface, the complex multi-layer bonding structure is eliminated, simplifying both the design and manufacturing process while achieving the same thermal insulation effect.
3Temperature
If thermal barrier coating is applied, then thermal insulation improves, but manufacturing precision requirements increase due to coating thickness control
Solution Approach 1:
The patent employs advanced coating techniques that allow precise control of coating parameters such as thickness, composition gradient, and microstructure. By controlling these parameters during the coating process (such as plasma spray, CVD, or PVD), the thermal insulation performance can be optimized without requiring excessive thickness variations. The coating thickness and properties can be tailored to achieve the desired thermal protection while maintaining manufacturing feasibility.
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 reduces cooling flow requirements, extends component life, and improves Thrust Specific Fuel Consumption (TSFC) with a weight reduction of approximately 2%-6% without modifying existing flange configurations.
Implementation Method 1
An intermediate bonding layer between the cavity and the non-metallic insert
Implementation Method 2
an abradable thermal barrier coating for enhanced durability
Data Source
AI summary
A Blade Outer Air Seal (BOAS) includes a body manufactured of a metal alloy, the body includes a face opposite a forward interface and an aft interface, the face includes a cavity. A non-metallic insert within the cavity such that the insert is flush with the face.