Floating Non-Contact Seal Lip Structure for Radial Motion Control
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Solution Overview
Problem
Floating non-contact seals in gas turbine engines face issues with wear and damage due to radial motion, leading to seal breakdown and leaks over time, as the shoe components can either come into contact with the seal elements or fall off, causing inefficiencies in fluid pressure regulation.
Innovation Solution
The seal assembly incorporates a nickel alloy-based floating non-contact seal with a spring system, a lip extension, and a unique manufacturing process using electro-discharge machining to create a lip structure that enhances the shoe's radial motion control and reduces the risk of seal damage, allowing for adaptive pressure regulation and improved sealing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If floating non-contact seal allows adaptive radial motion of shoe components, then sealing performance is improved by varying the gap between sealing element and rotating component, but sealing elements can break or become damaged against the shoe component over time
Solution Approach 1:
The patent applies local quality by creating a lip extension at the radial outward end of the shoe component. This lip structure provides localized protection at the critical sealing area where the sealing element contacts the shoe, preventing damage without restricting the overall adaptive radial motion of the entire shoe component. The lip acts as a protective barrier specifically at the sealing interface.
Solution Approach 2:
The lip extension serves as a protective barrier that prevents direct contact and potential damage between the sealing element and the shoe component body. By providing this protective structure in advance, the patent prevents damage before it can occur, allowing the sealing element to maintain its integrity while still permitting controlled radial motion for sealing performance.
2Adaptability or versatility
If shoe component moves radially inward and outward in response to pressure, then adaptive pressure regulation is achieved, but seal elements may come into contact with or fall off the shoe component
Solution Approach 1:
The patent employs a flexible sealing element that can deform and adapt to the radial motion of the shoe component. This flexible sealing element maintains contact with the rotating component for effective sealing while accommodating the pressure-driven radial movements of the shoe, preventing the seal from breaking or detaching during adaptive motion.
Solution Approach 2:
The lip extension provides a protective barrier that prevents the sealing element from falling off or becoming damaged during radial motion. By having this protective structure in place beforehand, the sealing element can freely move radially for pressure adaptation without risk of detachment or damage.
3Reliability
If knife-edge seal is used to form seal at interface, then initial sealing is achieved, but wear creates trench in honeycomb causing gaps and sporadic leaks
Solution Approach 1:
The patent replaces the traditional knife-edge mechanical contact seal with a floating non-contact seal system. This substitution eliminates the wear mechanism that creates trenches in the honeycomb structure, as the sealing element floats on a fluid film or magnetic field, preventing direct mechanical contact and the associated wear that leads to gaps and leaks over time.
Solution Approach 2:
The patent introduces an intermediary mechanism (floating seal element on fluid film or magnetic bearing) between the stationary honeycomb structure and the rotating component. This intermediary prevents direct contact and wear, maintaining sealing effectiveness over extended periods without creating trenches or gaps in the honeycomb structure.
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 effectively minimizes seal damage and leakage by allowing controlled radial motion of the shoe, maintaining tighter clearances and enhancing the stiffness of the seal assembly, thereby improving the durability and efficiency of fluid pressure regulation across the gas turbine engine components.
Implementation Method 1
a unique manufacturing process using electro-discharge machining to create a lip structure
Implementation Method 2
The seal assembly incorporates a nickel alloy-based floating non-contact seal with a spring system
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A seal assembly (10) includes an annular base (18), a spring (22), a shoe (20), a first channel (46), a seal cover (32), and a seal (34). The spring (22) includes a beam (24) and is connected to the annular base (18). The shoe (20) is disposed radially inward of the annular base (18) and connected to the spring (22). The shoe (20) includes an upstream portion (42), a downstream portion (44), and a lip (38) connected to and extending radially outward from the upstream portion (42) of the shoe (20). The spring (22) extends from the annular base (18) to the shoe (20). The first channel (46) is positioned between the shoe (20) and the beam (24) of the spring (22). The seal (34) is disposed between the seal cover (32) and the shoe (20) such that a downstream face (54) of the seal (34) is in contact with an upstream face (56) of the shoe (20).