Brush Seal Support Structure Yielding Under Radial Scraping Forces
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Solution Overview
Problem
Conventional brush seals for gas turbines are prone to damaging the rotor during incidents like bird strikes, and they compromise sealing efficiency due to either excessive clearance or notching, as they lack a scraping-tolerant design that can yield without exerting significant force on the rotor.
Innovation Solution
A brush seal design featuring a support structure with a spring-like elastic property that yields under radial scraping forces but maintains high axial stiffness, allowing for a minimal clearance between the rotor and support plate, thereby preventing damage and optimizing sealing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the clearance between the support element and the rotor is designed to be very small to improve sealing effect, then the sealing efficiency is improved, but the rotor may be damaged in case of damage incidents
Solution Approach 1:
The support element is designed with different stiffness characteristics for different directions: high axial stiffness to maintain sealing clearance and low radial stiffness to yield under scraping forces. This dynamic anisotropic behavior allows the support element to maintain small clearance for sealing while yielding to protect the rotor during damage incidents
Solution Approach 2:
The support element has non-uniform structural properties: the lateral surface is designed with lower stiffness to yield under radial scraping forces, while the axial direction maintains high stiffness to preserve sealing clearance. This local differentiation of mechanical properties resolves the contradiction between sealing efficiency and rotor protection
2Object-affected harmful factors
If the clearance between the support element and the rotor is designed to be large to protect the rotor, then the rotor is protected from damage, but the bundle leakage increases and sealing effect is reduced
Solution Approach 1:
The support element's directional stiffness characteristics enable it to maintain small clearance under normal operating conditions for optimal sealing, while yielding radially under extreme scraping forces to protect the rotor. This dynamic response eliminates the need for excessive clearance design
3Object-affected harmful factors
If the lateral surface of the support plate is coated to reduce rotor damage, then the rotor is protected, but only very small layer thicknesses are possible and sealing efficiency is compromised
Solution Approach 1:
Instead of relying on coating thickness, the invention changes the fundamental mechanical parameter of the support element's stiffness anisotropy. The support element is designed with inherently low radial stiffness and high axial stiffness, eliminating the need for thick protective coatings that would compromise sealing
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 design ensures the brush seal is scraping-tolerant, minimizing rotor damage and leakage while maintaining high sealing efficiency by allowing the support plate to yield under radial forces without applying significant counterforces, thus protecting the rotor and enhancing operational efficiency.
Implementation Method 1
the support structure will yield, preferably with a spring elastic effect
Data Source
AI summary
A brush seal for a gas turbine, in particular an aircraft engine, is disclosed. The brush seal includes a support ring which has a support plate and a support structure, where the support structure is arranged downstream with respect to the support plate. The brush seal also includes bristles which are arranged upstream with respect to the support ring, where ends of the bristles protrude radially inward beyond the support plate. The support structure yields when a scraping force acting radially outward occurs on a first lateral surface of the support structure, where the first lateral surface is directed radially inward, and the support structure does not yield when an axial operating force occurs on a second lateral surface of the support structure.