Angled Brush Seal Layout for Blade Outer Air Seal Leakage
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Solution Overview
Problem
Existing brush seals in gas turbine engines suffer from inefficiencies due to high-pressure cooling air leakage around blade outer air seals, leading to inefficiencies and undesirable mixing with combustion products, particularly when formed with ceramic matrix composites.
Innovation Solution
The brush seals are angled relative to the rotational axis, with an axial component towards the trailing or leading edge attachment features, forming an angle between 15 and 75 degrees, to effectively resist pressure differentials and maintain sealing contact with the sealing surface, even when manufactured with ceramic matrix composites.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a brush seal extends radially inwardly with only a tangential angle to prevent buckling, then structural stability is improved, but sealing effectiveness deteriorates due to inability to resist pressure differentials
Solution Approach 1:
The brush seal bristles are configured to extend at an angle that includes both a radial component and an axial component, transitioning from a purely tangential orientation to a three-dimensional orientation. This angular configuration allows the bristles to simultaneously resist buckling radially while effectively blocking pressure differentials axially, resolving the contradiction between structural stability and sealing effectiveness.
2Temperature
If cooling air is directed into the chamber at high pressure, then cooling effectiveness is improved, but leakage around the blade outer air seal increases
Solution Approach 1:
The high-pressure cooling air that was causing harmful leakage around the blade outer air seal is now effectively contained by the angled brush seal. The brush seal converts the potentially harmful high-pressure leakage flow into a beneficial sealed flow path, maintaining cooling effectiveness while eliminating energy loss through leakage.
3Ease of manufacture
If the brush seal bristles extend perpendicular to the rotational axis, then manufacturing simplicity is improved, but sealing contact with angled surfaces deteriorates
Solution Approach 1:
The brush seal bristles are configured with a specific angular orientation that varies according to the local sealing surface geometry. Rather than using a uniform perpendicular-to-axis orientation, the bristles are angled to match the specific contact surface requirements, ensuring optimal sealing contact precision while maintaining manufacturability through defined angular parameters.
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 angled design enhances sealing efficiency by maintaining contact with the sealing surface, reducing leakage, and improving the overall performance of the gas turbine engine, especially when used with ceramic matrix composite components.
Implementation Method 1
to account for a pressure differential across the brush seal
Data Source
Figure 1
Figure 2A~2B
Figure 3~6
AI summary
There is a blade outer air seal (102) positioned to be radially outward of blades (101) in the rotating blade row (101) relative to the rotational axis (X). There is at least one brush seal (124; 128) having bristles (132) extending from a mount location (111) radially inward to contact a sealing surface (116; 114) on the blade outer air seal (102). An angle (A) is defined between the bristles (132) and relative to the sealing surface (116; 114) having a radially inward extending component, and with an axial component in a direction toward a leading edge attachment feature (104) and a trailing edge attachment feature (108), and the angle (A) is less than 90° on a side of the brush seal (124; 128) opposite the leading edge and trailing edge mount hooks (104; 108). A gas turbine engine component is also disclosed.