Piston Ring Shuttle Carrier for Gas Turbine Sealing
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Solution Overview
Problem
The existing piston ring seals in gas turbine engines experience significant wear due to relative motion between the tie shaft and rotor disc, leading to deterioration of the seal's function over time.
Innovation Solution
A seal assembly is introduced, comprising a shuttle located on the radial outer surface of the tie shaft, which is freely axially movable, and a piston ring seal retained in the shuttle and engaged with the rotor. This design allows the shuttle to move axially with the tie shaft while the piston ring seal remains stationary relative to the rotor, reducing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a piston ring seal is used to seal between the tie shaft and rotor disc, then sealing between adjacent cavities is achieved, but relative motion causes significant wear to the piston ring seal and mating parts
Solution Approach 1:
The seal assembly is divided into two functional components: a stationary piston ring seal that remains fixed relative to the rotor disc, and a movable shuttle carrier that absorbs the relative motion between the tie shaft and rotor disc. This segmentation allows the sealing surface to remain stationary while the carrier handles the mechanical displacement, eliminating wear on the seal.
Solution Approach 2:
The shuttle carrier acts as an intermediary element between the tie shaft and the piston ring seal. It is retained on the tie shaft and can move axially to accommodate relative motion, while simultaneously carrying the piston ring seal in a stationary position relative to the rotor disc. This intermediary component isolates the seal from harmful relative motion.
2Adaptability or versatility
If the piston ring seal is retained directly on the tie shaft, then the seal can accommodate relative motion, but the seal experiences damaging wear and deterioration
Solution Approach 1:
The system is segmented into a motion-absorbing component (shuttle carrier) and a stationary sealing component (piston ring seal). The shuttle carrier is retained on the tie shaft and accommodates all relative motion, while the piston ring seal is carried by the shuttle and remains stationary relative to the rotor disc, ensuring reliable sealing without wear.
Solution Approach 2:
The shuttle carrier serves as an intermediary that is retained on the tie shaft but carries the seal in a different reference frame. This allows the seal to be decoupled from the relative motion between the tie shaft and rotor disc, maintaining both adaptability to motion and reliability of sealing function.
Data Source
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AI summary
A rotating assembly of a gas turbine engine includes a first rotating component 86; and a second rotating component 66 located radially outboard of the first rotating component 86, relative to an engine central longitudinal axis. A seal assembly 84 is configured to seal between the first rotating component 86 and the second rotating component 66. The seal assembly 84 includes a shuttle 92 located on a radial outer surface 94 of the second component 66 and freely axially movable along the radial outer surface 94 and a piston ring seal 88 retained in the shuttle 92 and engaged with the first rotating component 86. Axial motion of the first rotating component 86 relative to the second rotating component 66 urges movement of the shuttle 92 along the radial outer surface 94 of the second rotating component 66, while the position of the piston ring seal 88 remains stationary relative to the first rotating component 86.