Angled Brush Seal Geometry for Blade Outer Air Seal Leakage
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Solution Overview
Problem
In gas turbine engines, high-pressure cooling air leaks into the combustion products due to the pressure differential across brush seals, leading to inefficiencies and reduced performance.
Innovation Solution
The brush seals are designed with bristles extending radially inwardly at an angle less than 90°, with an axial component towards the leading or trailing edge attachment features, to effectively contact the sealing surface and mitigate leakage, utilizing ceramic matrix composite components for enhanced sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If brush seals extend radially inwardly perpendicular to the rotational axis, then the sealing contact is maximized, but the pressure differential causes buckling and reduced sealing effectiveness
Solution Approach 1:
The brush seal is designed with an asymmetric angle relative to the radial direction, specifically angled between 10-80 degrees from the radial direction. This asymmetric configuration prevents the bristles from buckling under pressure differential while maintaining effective sealing contact with the blade outer air seal surface.
Solution Approach 2:
The invention changes the geometric parameter of the brush seal orientation from the conventional perpendicular-to-axis configuration to a specific angled configuration (10-80 degrees from radial direction). This parameter change optimizes the balance between sealing effectiveness and structural stability under pressure differential.
2Temperature
If cooling air pressure is increased to improve cooling efficiency, then cooling performance improves, but leakage around the blade outer air seal increases
Solution Approach 1:
The brush seal is positioned at a specific location on the blade outer air seal with a localized angled configuration (10-80 degrees from radial direction) to specifically address the leakage issue at the seal interface, while allowing the rest of the cooling air system to maintain high pressure for effective cooling.
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 configuration reduces leakage by optimizing the contact between bristles and the sealing surface, improving the sealing efficiency and maintaining engine performance despite high-pressure differentials.
Implementation Method 1
there is a tendency for the high pressure cooling air to leak around the BOAS and into the products of combustion
Implementation Method 2
a brush seal having bristles extending from a mount location radially inward to contact a sealing surface
Data Source
AI summary
There is a blade outer air seal positioned to be radially outward of blades in the rotating blade row relative to the rotational axis. There is at least one brush seal having bristles extending from a mount location radially inward to contact a sealing surface on the blade outer air seal. An angle is defined between the bristles and relative to the sealing surface having a radially inward extending component, and with an axial component in a direction toward a leading edge attachment feature and a trailing edge attachment feature, and the angle is less than 90° on a side of the brush seal opposite the leading edge and trailing edge mount hooks. A gas turbine engine component is also disclosed.