Seal Shoe Support Plate Layout for Wear and Vibration Control
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Solution Overview
Problem
Existing seal assemblies in gas turbine engines face challenges in preventing unwanted movement and vibration of shaft components, leading to potential violent vibrations and increased wear rates due to inadequate contact pressure and surface area.
Innovation Solution
A seal arrangement featuring a support plate coupled to a shoe, which moves radially with the shoe and seal ring, increasing the contact surface area and reducing friction, while being replaceable and manufactured separately to allow for additional manufacturing capabilities and weight reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the seal shoe contacts the seal ring directly, then the contact pressure is sufficient, but the contact surface area is limited leading to increased wear rates
Solution Approach 1:
The seal assembly is divided into distinct components: a seal shoe, a support plate, and a seal ring. The support plate acts as an intermediate segment between the shoe and seal ring, distributing the contact pressure across a larger surface area while maintaining adequate pressure through the structured interface between components.
Solution Approach 2:
The support plate serves as an intermediary element between the seal shoe and seal ring. This mediator increases the contact surface area without compromising the necessary contact pressure, as the support plate is specifically designed to distribute loads effectively across its interface with the seal ring.
2Loss of substance
If the seal shoe area is increased to reduce wear, then the contact surface area increases, but the natural frequency decreases leading to violent vibrations
Solution Approach 1:
By segmenting the seal structure into a shoe, support plate, and seal ring, the system achieves the benefits of increased contact area without the adverse effects on natural frequency. The support plate's specific geometry and material properties allow it to maintain structural stability and natural frequency while providing the necessary contact surface area.
Solution Approach 2:
The support plate is designed with specific local properties - its thickness, material composition, and geometric features are optimized to provide increased contact surface area in the radial direction while maintaining the natural frequency characteristics needed to prevent violent vibrations. The local quality of the support plate interface is tailored to address wear without compromising stability.
3Device complexity
If the seal shoe is made as a single integrated component, then the structure is simple, but manufacturing capabilities are limited and weight cannot be optimized
Solution Approach 1:
The seal assembly is segmented into a seal shoe, support plate, and seal ring that can be manufactured separately using different processes and materials optimized for each component's specific requirements. This segmentation enables advanced manufacturing capabilities while the structured assembly maintains structural integrity and simplicity.
Solution Approach 2:
The support plate serves multiple functions: it increases contact surface area, distributes pressure, maintains natural frequency, and provides a replaceable wear surface. This multi-functionality is achieved through a single component design that integrates several benefits without requiring multiple separate parts, thus maintaining structural simplicity while enabling manufacturing optimization.
4Manufacturing precision
If the seal components are fixed in position, then the alignment is precise, but the range of travel is limited
Solution Approach 1:
The seal assembly incorporates dynamic characteristics through the support plate's ability to move radially with the seal ring while maintaining proper alignment. The interface between the support plate and seal ring is designed to accommodate radial movement and range of travel while preserving the precise alignment needed for effective sealing and pressure distribution.
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 reduces wear rates, increases the natural frequency of the shoe, and enhances the safety margin between seal natural frequency and rotational frequency, preventing violent vibrations and allowing for a greater range of travel while maintaining a lower coefficient of friction.
Implementation Method 1
increasing the contact surface area and reducing friction
Implementation Method 2
preventing unwanted movement and vibration of shaft components
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A seal arrangement (200) comprises a seal (214) comprising an outer ring (230), a shoe (232), and an arm (234) extending between the shoe (232) and the outer ring (230), wherein the shoe (232) moves relative to the outer ring (230) via the arm (234), a seal ring (216) adjacent the seal (214), and a support plate (240) disposed between the seal (214) and the seal ring (216), wherein the support plate (240) moves together with the shoe (232) in a radial direction relative to the seal ring (216).