Split Piston Ring Seal Geometry for Reduced Interface Wear
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Solution Overview
Problem
Piston ring seals in gas turbine engines experience increased wear due to pressure, thermo-mechanical deflections, and vibratory effects, particularly at the edges where thermal expansion and vibrations are more pronounced.
Innovation Solution
A piston ring seal arrangement with a circumferentially split ring configuration, where the first axially-facing side has fewer edges than the second, and a convex radius is formed at the edges to reduce contact and wear. The arrangement includes a first end pocket and a second end finger configured to be received in the pocket, optimizing the seal's interaction with mating components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the piston ring seal has a circumferentially split ring configuration with multiple edges, then the seal can be installed into the groove and maintain structural integrity, but the number of edges increases contact points with mating components leading to increased wear
Solution Approach 1:
The piston ring seal is divided into a circumferentially split ring configuration with a first circumferential end and a second circumferential end, allowing installation into the groove while controlling the number of edges at each axially-facing side to minimize wear contacts
Solution Approach 2:
The first axially-facing side is designed with fewer edges compared to the second axially-facing side, creating asymmetric edge distribution that reduces wear at the primary contact interface while maintaining seal functionality
2Adaptability or versatility
If the edges of the piston ring seal are located at the free ends to accommodate thermal expansion and vibrations, then the seal can absorb thermal expansion and respond to vibrations, but this results in increased wear at the piston ring seal to mating part interface
Solution Approach 1:
A convex radius is formed at the edges of the piston ring seal, replacing sharp edges with curved surfaces. This curvature distributes contact pressure more evenly across the mating interface, reducing stress concentration and wear while still allowing the free ends to accommodate thermal expansion and vibrations
3Reliability
If the operating pressure is greater at one axially-facing side, then the seal can maintain sealing force, but this creates asymmetric wear patterns at the edges
Solution Approach 1:
The asymmetric edge distribution between the first and second axially-facing sides is designed to accommodate the asymmetric pressure distribution, with fewer edges at the high-pressure side to minimize wear while maintaining adequate 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 solution reduces wear at the piston ring seal to mating part interface by minimizing the number of edges in contact and utilizing convex radii to distribute pressure more evenly, thereby enhancing the durability and efficiency of the seal.
Implementation Method 1
utilizing convex radii to distribute pressure more evenly
Implementation Method 2
edges of the piston ring seals contacting the mating parts and interacting therewith
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A piston ring seal arrangement of a gas turbine engine includes a piston ring (64) having a circumferentially split ring configuration having a first axially-facing side (72) and a second axially-facing side (70) opposite the first axially facing side (72). The piston ring (64) includes a first circumferential end (78) circumferentially overlapping a second circumferential end (80). The piston ring (64) is installed into a groove (66) in a mating component (62). The first circumferential end (78) and the second circumferential end (80) define a plurality of edges (90... 112) on the first axially-facing side (72) and the second axially-facing side (70). The first axially-facing side (72) includes fewer edges (90...112) than the second axially-facing side (70), and an operating pressure acting on the piston ring (64) is greater at the second axially-facing side (70) than at the first axially-facing side (72).