Intershaft Seal Asymmetric Ring Segments Wear Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Intershaft seals in gas turbine engines face challenges with wear, heating, fracture, and failure due to direct contact with end rings and inadequate frictional resistance, leading to leakage and overheating issues.
Innovation Solution
A seal assembly featuring a sealing ring with asymmetric ring segments, centrifugal retaining plates, and end rings, where the asymmetric ring segments have vertical and horizontal flanges with slots and tabs, allowing for non-contact sealing and reduced frictional wear by centrifugal expansion and radial movement, thereby minimizing direct contact and stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the seal element is forced onto the rotating outer shaft by centrifugal forces and pressure loading, then the seal element rotates with the outer shaft, but direct contact between the seal element and end rings causes wear, heating, and frictional wear
Solution Approach 1:
The patent introduces end rings as intermediary components between the seal element and the shaft ends. These end rings absorb the direct contact and friction, preventing the seal element from directly contacting the shaft ends. The end rings rotate with the inner shaft while the seal element rotates with the outer shaft, creating a protective buffer that reduces wear and heating on the critical sealing surfaces.
Solution Approach 2:
The seal assembly is divided into distinct functional segments: the seal element for sealing, the end rings for protection and rotation control, and the inner/outer shafts for structural support. This segmentation allows each component to perform its specific function optimally, with the end rings specifically designed to handle the mechanical contact and rotation, thereby protecting the seal element from harmful wear and heating.
2Reliability
If the seal element is designed to induce an outward radial load to prevent axial load movement, then sealing effectiveness is improved, but frictional resistance is inadequate leading to leakage and overheating
Solution Approach 1:
The end rings serve as mediators that provide the necessary frictional resistance and heat dissipation capability. By placing these high-friction, heat-resistant components at the contact points with the shafts, the system achieves adequate frictional resistance without compromising the seal element's radial loading and sealing function. The end rings effectively manage the thermal and frictional aspects while the seal element focuses on maintaining the sealing interface.
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, heating, and failure of the sealing ring by maintaining a non-contact seal during rotation, allowing the seal to function as a full ring bushing and minimizing frictional wear and stress, thus enhancing the durability and performance of the intershaft seal.
Implementation Method 1
engagement between the asymmetric ring segments and the tabs results from centrifugal forces imparted onto the asymmetric ring segments during rotation of the inner shaft
Data Source
AI summary
An intershaft seal assembly for use between an inner shaft and an outer shaft within a turbine engine is presented. The seal assembly includes a sealing ring, centrifugal retaining plates, and end rings. The sealing ring further includes a plurality of asymmetric ring segments whereby each asymmetric ring segment further includes a vertical flange and horizontal flanges extending from the vertical flange in a non-symmetric arrangement. At least one slot is disposed along each horizontal flange. The sealing ring is interposed between the centrifugal retaining plates. Each centrifugal retaining plate includes a plurality of tabs extending therefrom. Each tab is engaged by one slot. The sealing ring and the centrifugal retaining plates are interposed between the end rings. Each centrifugal retaining plate is directly interposed between one horizontal flange and one end ring. The vertical flange extends from between the end rings in the direction of the outer shaft. A non-contact seal is formed between an outer sealing surface along the vertical flange and an inner sealing surface along the outer shaft.