Gas Turbine Piston Ring Seal Geometry for Edge Wear Reduction
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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 contacting mating parts.
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.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the piston ring seal has a continuous ring configuration, then the sealing effectiveness is improved, but the wear at the edges contacting mating parts increases due to pressure, thermo-mechanical deflections, and vibratory effects
Solution Approach 1:
The continuous ring configuration is segmented into a first circumferential end and a second circumferential end, creating an asymmetric edge distribution where one end has fewer edges than the other, reducing wear at the mating part interface while maintaining sealing effectiveness
Solution Approach 2:
The piston ring seal employs asymmetric edge distribution with the first axially-facing side having fewer edges than the second axially-facing side, positioning fewer wear-prone edges at the high-pressure side to reduce overall wear and extend service life
2Manufacturing precision
If the edges of the piston ring seal are sharp, then the manufacturing precision is improved, but the wear at the contact interface increases due to concentrated pressure and vibrations
Solution Approach 1:
Convex radii are formed at the edges of the piston ring seal, replacing sharp edges with curved surfaces. This distributes the contact pressure more evenly across the mating part interface, reducing stress concentration and wear while maintaining manufacturing precision through controlled radii
3Reliability
If the piston ring seal is positioned to maximize sealing contact, then the sealing effectiveness is improved, but the wear increases due to thermo-mechanical deflections and vibratory effects at the free ends
Solution Approach 1:
Different regions of the piston ring seal are given different properties: the asymmetric edge distribution concentrates fewer edges at the high-pressure sealing side, while the convex radii at the edges provide localized stress distribution. This local differentiation reduces wear at critical contact points while maintaining overall sealing effectiveness
Data Source
AI summary
A piston ring seal arrangement of a gas turbine engine includes a piston ring having a circumferentially split ring configuration having a first axially-facing side and a second axially-facing side opposite the first axially facing side. The piston ring includes a first circumferential end circumferentially overlapping a second circumferential end. The piston ring is installed into a groove in a mating component. The first circumferential end and the second circumferential end define a plurality of edges on the first axially-facing side and the second axially-facing side. The first axially-facing side includes fewer edges than the second axially-facing side, and an operating pressure acting on the piston ring is greater at the second axially-facing side than at the first axially-facing side.