Vertical Brush Seal Layout for Hot-Gas Turbomachine Gaps
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Solution Overview
Problem
Existing static seal arrangements in turbomachines face challenges with high-temperature creep reducing the sealing effectiveness and requiring large installation spaces, especially when equilibrating axial displacements and protecting against hot gases.
Innovation Solution
A vertical brush seal arrangement is used, positioned radially outside the gap with its bristles extending inward, forming both radial and axial sealing sites, protected from high temperatures and cooled by sealing air, allowing for adjustable bristle configuration to equilibrate displacements and prevent thermal stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a piston ring is used for static sealing, then sealing function is provided, but prestressing is strongly reduced due to creep at high temperatures
Solution Approach 1:
The sealing function is extracted from the piston ring and transferred to a separate sealing element that is not subjected to the same thermal and mechanical stresses, allowing the piston ring to maintain its structural integrity while the sealing element provides reliable sealing
Solution Approach 2:
A cooling medium is introduced as an intermediary between the hot gas and the sealing element, absorbing heat and preventing thermal damage to the sealing components, thereby maintaining prestressing and sealing effectiveness
2Stability of the object's composition
If a sealing plate is used to equilibrate axial displacements, then axial displacement compensation is achieved, but large radial height and installation space are required
Solution Approach 1:
The sealing element is designed with flexible bristles that can dynamically adapt to axial displacements through elastic deformation, eliminating the need for a rigid sealing plate with large radial height while maintaining effective sealing
Solution Approach 2:
The sealing element uses a flexible brush structure with multiple bristles that can bend and deform to accommodate axial movements between components, providing displacement compensation with minimal radial space requirement
3Reliability
If brush seal bristles are exposed to hot gas, then sealing action is provided, but plastic deformations of the brush package occur
Solution Approach 1:
A cooling medium is introduced as a protective intermediary between the hot gas and the brush seal bristles, absorbing thermal energy and preventing plastic deformation of the brush package while allowing the sealing element to maintain contact and sealing action
Solution Approach 2:
The cooling medium provides beforehand cushioning by absorbing heat before it can reach the brush seal bristles, preventing thermal damage and plastic deformation in advance while maintaining sealing effectiveness
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 maintains effective sealing at high temperatures, equilibrates radial and axial displacements, and reduces the risk of bristle deformation, enhancing the turbomachine's efficiency and stability while minimizing the risk of hot gas exposure.
Implementation Method 1
By bending the bristles or the bristle wires, radial displacements at the radial sealing site of the brush seal can be equilibrated
Implementation Method 2
The brush package is reliably applied at the axial sealing site by a pressure difference resulting during the operation of the turbomachine
Implementation Method 3
The brush seal is arranged outside the flow of hot gas and thus is protected from high temperatures. The axial overlapping of the first and second components brings about a reliable heat protection of the brush seal relative to high temperatures
Data Source
AI summary
Disclosed is a static seal arrangement for sealing a gap between a first static component and a second static component of a turbomachine such as an aircraft engine or a static gas turbine, having a brush seal held distant from a hot gas, this brush seal being arranged standing or vertical with its clamping section that can be surrounded by cooling air in a radially outer clamping space relative to the gap, and forming a radial sealing site with the first component and an axial sealing site with the second component; also disclosed is a turbomachine.