Split Annular Ring Curvature for Turbomachine Groove Sealing
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Solution Overview
Problem
Existing split metal rings in turbine engine rotor elements experience non-uniform elastic deformation, leading to incomplete contact with the annular groove, allowing air and gas leakage, solid particle deposition, and subsequent damage due to centrifugal forces.
Innovation Solution
A split annular ring with end portions designed as arcs of a circle having a radius of curvature equal to or slightly less than the annular groove, ensuring uniform contact and preventing particle deposition during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a split metal ring is mounted elastically constrained in an annular groove with uniform radius of curvature, then the ring can be easily manufactured and installed, but the end portions do not come into contact with the groove bottom due to non-uniform deformation, leading to incomplete sealing and particle deposition
Solution Approach 1:
The ring is designed with non-uniform radius of curvature where the end portions have a smaller radius than the intermediate portions. This local variation in geometry compensates for the non-uniform elastic deformation that occurs during mounting, ensuring that the end portions make contact with the groove bottom while intermediate portions remain elevated, thus achieving complete sealing without compromising manufacturing simplicity
Solution Approach 2:
The ring is pre-formed with a specific non-uniform radius of curvature profile before mounting. This preliminary shaping anticipates the deformation that will occur when the ring is elastically constrained in the groove, pre-positioning the end portions to ensure contact with the groove bottom after installation, thereby preventing particle deposition from the outset
2Reliability
If the end portions of the ring are designed with smaller radius of curvature, then complete contact with the groove is achieved, but the deformation distribution becomes highly non-uniform, increasing stress concentration
Solution Approach 1:
The ring incorporates localized variations in radius of curvature specifically at the end portions, while maintaining a more uniform curvature in the intermediate sections. This differential design ensures contact at critical locations (ends) while distributing stress more evenly across the structure, preventing excessive stress concentration that would compromise the ring's strength
Solution Approach 2:
The ring's cross-sectional geometry is optimized with specific curvature radii at different locations. The end portions have smaller radius of curvature to ensure groove contact, while intermediate portions have larger radii to reduce stress concentration. This curvature distribution creates a balance between achieving complete contact and maintaining structural integrity under operational loads
3Use of energy by moving object
If air and gases circulate between the rod and groove bottom, then cooling and thrust generation are improved, but solid particles are conveyed and deposited in the gap, causing damage to rotating parts
Solution Approach 1:
The invention eliminates the harmful gap between the ring end portions and the groove bottom by designing the ring geometry to ensure contact at these locations. By removing this space, the pathway for solid particles to be conveyed and deposited is eliminated, while the beneficial circulation of air and gases for cooling and thrust generation is maintained in the annular passage between the ring and rotor element
4Object-generated harmful factors
If centrifugal forces are applied to compress particles between the rod and groove bottom, then particle removal is attempted, but the forces are insufficient to destroy particles while applying high pressure that damages the rod and rotor
Solution Approach 1:
The invention prevents particle accumulation by eliminating the gap where particles would be compressed during rotation. By ensuring the ring end portions contact the groove bottom, no space remains for particle lodgment, thereby avoiding the harmful effect of centrifugal compression that damages both the ring and rotor while still allowing particle removal through the elimination of the trapping mechanism
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
Ensures complete contact between the ring and the groove, preventing air leakage and solid particle deposition, thereby extending the lifespan of the rotating parts and reducing wear.
Implementation Method 1
the elastic deformation of the rod in the groove is not uniform over its entire circumferential extent
Implementation Method 2
During rotation of the rotor, the end portions of the rod are applied to the bottom of the annular groove by centrifugal forces
Implementation Method 3
The operation of the turbomachine causes micro-movements and friction of the rod in the annular groove of the rotor, which dissipate energy and at least partially dampen the vibratory phenomena
Data Source
Figure 1
Figure 2~3
AI summary
Split annular ring (38) intended to be mounted pre-stressed elastically in an annular groove (24) of a rotating part (10) of a turbomachine and having in the free state a diameter greater than that of the groove (24), characterized in that in the free state without stress, the end parts (40, 42) of the ring (38) are arcs of circles having a radius of curvature substantially equal to that of the annular groove (24).