Abradable Liner Cooling via Segmented Cell Walls
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Solution Overview
Problem
Existing abradable liners in gas turbine engines face challenges with effective cooling due to sintered powder coatings, leading to increased oxidation and premature degradation, which complicates the management of the gap between rotor blade tips and the engine casing.
Innovation Solution
The introduction of through-holes in the abradable component's walls allows for the delivery of cooling air to the gas-washed surface, with blind holes that expose to provide increased cooling as the component wears, and the use of sintered powder material within open-faced cells to maintain durability and prevent oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sintered powder coating is applied to the honeycomb liner, then oxidisation protection and sealing with the blade tip are improved, but effective cooling of the liner surface becomes more difficult, leading to increased oxidation and premature degradation
Solution Approach 1:
The liner is divided into multiple cells with walls that contain cooling channels. This segmentation allows cooling air to be delivered to specific locations on the liner surface through the cell walls, providing localized cooling while maintaining the overall protective function of the sintered powder coating.
Solution Approach 2:
The cell walls act as intermediaries that transmit cooling air from the interior of the liner to the outer surface. The walls contain cooling channels that deliver cooled air to the gas-washed surface, enabling the sintered powder coating to maintain its protective function while the liner surface remains cooled.
2Productivity
If the gap between rotor blade tips and engine casing is closely controlled, then air leakage is minimised, but the complexity of managing the gap increases due to wear and oxidation issues
Solution Approach 1:
The abradable liner is designed to wear preferentially to the blade tips, automatically adjusting the gap size during operation. The cooling system self-regulates by delivering cooling air through the cell walls as the liner wears, maintaining the protective function while reducing the need for complex external gap management systems.
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 cooling arrangement enhances the durability and longevity of the abradable liner by providing adaptive cooling that increases as wear progresses, reducing oxidation and maintaining a close fit between rotor blades and the engine casing.
Implementation Method 1
at least one wall includes one or more through-holes for providing a flow of cooling air from the outboard side to the gas washed surface of the abradable network of open faced cells
Implementation Method 2
Such abradable honeycomb liners (or lands) often include a sintered powder coating within the honeycombs which helps provide increased oxidisation protection
Data Source
AI summary
Described is an abradable component for a gas turbine engine that includes a base having an outboard side which receives a supply of cooling air in use and an inboard side with a plurality of walls thereon. The walls intersect one another to define an abradable network of open faced cells on a gas washed surface thereof, and at least one of the walls includes one or more through-holes for providing a flow of cooling air from the outboard side to the gas washed surface of the abradable network of open faced cells, when in use.