Bearing-Supported Floating Seal for Low-Friction Adaptive Sealing
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Solution Overview
Problem
Adaptive seals in gas turbine engines face reduced effectiveness and wear due to friction between moving and stationary components, which affects their ability to maintain sealing under varying fluid flow and structural movement.
Innovation Solution
A seal design featuring dual beams and roller bearings arranged in pockets at the interface between the floating shoe and the scalloped plate, allowing the shoe to move radially and maintain equilibrium position without excessive friction, thus reducing wear and enhancing sealing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If floating components are used to provide adaptive sealing, then sealing effectiveness under varying fluid flow and movement is improved, but friction between moving and stationary components increases, reducing seal effectiveness and causing wear
Solution Approach 1:
A fluid film is introduced as an intermediary between the floating seal component and the stationary structure. This fluid film separates the moving and stationary surfaces, enabling the floating component to move radially in response to pressure gradients while minimizing direct friction and wear between solid surfaces.
Solution Approach 2:
The patent utilizes fluid pressure (hydraulic principle) to support the floating seal component. The fluid pressure gradient across the seal face generates a lifting force that enables radial movement of the floating component, allowing adaptive sealing while reducing mechanical friction through fluid-based support.
2Reliability
If floating components move to adapt to pressure changes, then sealing performance is improved, but wear on seal components increases due to friction
Solution Approach 1:
The fluid film acts as a protective intermediary layer between the floating seal component and the stationary structure. This intermediary prevents direct solid-to-solid contact during radial movement, significantly reducing wear on both the floating component and the stationary sealing surface, thereby extending component life while maintaining sealing performance.
Solution Approach 2:
The patent changes the physical state and properties of the interface between moving and stationary components by introducing a fluid film. This parameter change transforms the interaction from solid-to-solid friction to fluid-based support, reducing wear while enabling the necessary radial movement for adaptive sealing.
3Adaptability or versatility
If friction is reduced to maintain floating component movement, then adaptability is improved, but sealing force may be reduced
Solution Approach 1:
The patent optimizes the parameters of the fluid film, including its viscosity, pressure distribution, and thickness, to simultaneously enable floating component mobility and maintain adequate sealing force. By carefully controlling these fluid parameters, the system achieves both low friction for adaptability and sufficient contact pressure for effective sealing.
Solution Approach 2:
The patent applies partial action by allowing the floating component to move only to the extent necessary to balance the pressure gradient, rather than complete freedom of movement. This controlled partial movement maintains sealing effectiveness while minimizing friction, achieving an optimal balance between adaptability and sealing force.
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 seal design maintains effective sealing by minimizing friction and wear, ensuring consistent clearance between static and rotating structures despite changes in fluid pressure and structural movement, thereby improving the durability and performance of the seal.
Implementation Method 1
at least one bearing arranged at the interface between the shoe and the downstream side of the plate
Implementation Method 2
a pressure gradient of the fluid causes the shoe to move radially with respect to an engine axis to an equilibrium position
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3C
AI summary
A seal (200) according to the present disclosure includes a plate, and a floating shoe (200B) supported with respect to the plate (208) in a first direction. The floating shoe (200B) has a sealing feature (200C) extending in a second direction perpendicular to the first direction. At least one bearing (209) is between the plate (208) and the floating shoe (200B). The bearing (209)is configured to facilitate movement of the floating shoe (200B) with respect to the plate (208) in the second direction. A gas turbine engine including the seal and a method of sealing a rotating component with respect to a stationary component are also disclosed.