Curved Ring-Segment Seals for Turbine Leakage Control
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Solution Overview
Problem
Leakage between sealing pads in turbine assemblies leads to significant reinjection of air into the turbine stream, reducing efficiency and performance.
Innovation Solution
The use of curved sealing tabs and tongues in an annular structure with grooves that allow for bending under air pressure, dynamically sealing the gap between ring sectors and reducing air passage from outside to inside.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If straight sealing tabs and tongues are used in the ring sectors, then the assembly is simple and easy to manufacture, but air leakage occurs between the sealing components
Solution Approach 1:
The sealing tabs and tongues are designed with curved geometries instead of straight lines. The curved shape allows the sealing components to conform to the circular arrangement of ring sectors and enables them to flex under air pressure to maintain contact, thereby improving sealing effectiveness while accommodating the radial arrangement of sectors.
Solution Approach 2:
The sealing structure transitions from a static rigid configuration to a dynamic flexible system. The curved sealing tabs and tongues can bend and deform under the action of air pressure differential, allowing them to adaptively maintain sealing contact during turbine operation, thus improving reliability without requiring overly complex mechanical systems.
2Ease of manufacture
If multiple ring sectors are arranged end to end to form an annular structure, then the turbine assembly can be manufactured and assembled more easily, but gaps between adjacent sectors create leakage paths
Solution Approach 1:
The annular distributor is divided into multiple discrete ring sectors that can be manufactured separately and then assembled end-to-end. This segmentation enables easier manufacturing and assembly of large-diameter components while the curved sealing tabs and tongues bridge the gaps between segments to prevent leakage, thus resolving the contradiction between manufacturability and energy loss.
Solution Approach 2:
The curved sealing tabs and tongues act as intermediary elements between adjacent ring sectors. These sealing components fill and seal the gaps that necessarily exist between segmented ring sectors, preventing air leakage while allowing the segmented structure to maintain its manufacturing and assembly advantages.
3Productivity
If air pressure is allowed to act between adjacent connection faces, then the turbine operates efficiently, but this pressure causes sealing components to deform and leak
Solution Approach 1:
The air pressure differential that naturally exists during turbine operation and causes leakage in rigid sealing systems is converted into a beneficial force. The pressurized air acts on the curved sealing tabs and tongues, causing them to bend and press tighter against each other, thereby improving the seal rather than compromising it. The harmful pressure gradient becomes the mechanism that ensures sealing integrity.
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
Effectively reduces or eliminates leaks between ring sectors, enhancing the seal and maintaining turbine efficiency by utilizing air pressure to press the sealing components against each other.
Implementation Method 1
the first sealing tongue and the second sealing tongue have a degree of freedom in bending starting from their position of mounting in the presence of an air pressure exerted from upstream to downstream between the adjacent connection faces of the at least two adjacent ring sectors during operation of the turbine
Implementation Method 2
the first sealing tongue and the second sealing tongue have a degree of freedom in bending starting from their position of mounting in the presence of an air pressure exerted from upstream to downstream
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a turbine assembly (1) comprising an annular structure extending circumferentially about an axial direction (DA) and comprising ring segments (10) arranged circumferentially end to end and comprising adjacent connection faces (13a), coupled by sealing tongues (21, 22), in the wall (11) and in the flange (12). The invention is characterised in that the grooves (31, 32) and tongues (21, 22) are curved, the tongues (21, 22) having a bending degree of freedom in respect of their mounting positions when air pressure is exerted from upstream to downstream between the adjacent connection faces (13a) during operation of the turbine, tongue (22) having a contact point (220) with a point (213) on tongue (21).