Turbine Ring Segment Sealing With Curved Tabs for Air Leak Reduction
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Solution Overview
Problem
Turbine assemblies experience significant air leaks between sealing plates due to air flow from the external side into the turbine stream, leading to inefficiencies and performance issues.
Innovation Solution
The use of curved sealing tabs and grooves that allow for bending under air pressure, enhancing the sealing contact between adjacent ring sectors and reducing air leakage by dynamically adjusting to the aerodynamic stream during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If rigid sealing plates are used to seal the gap between adjacent ring sectors, then the sealing structure is simple and easy to manufacture, but air leaks significantly between the sealing plates due to pressure differential
Solution Approach 1:
The sealing tabs are designed to be flexible rather than rigid, allowing them to dynamically adjust their position in response to air pressure differential. The tabs bend to follow the aerodynamic stream, maintaining continuous contact with the sealing surface and adapting to operational conditions, thereby eliminating the air leakage problem inherent in rigid sealing structures.
Solution Approach 2:
The sealing tabs are made of elastomeric material that changes its physical state based on applied pressure. Under air pressure differential, the tabs deform from their initial configuration to a bent configuration, changing their geometric parameters to maintain sealing contact. This parameter change allows the seal to respond dynamically to operating conditions.
2Reliability
If the sealing tabs are made flexible to reduce air leakage, then sealing efficiency improves, but the manufacturing precision and control of tab geometry become more difficult
Solution Approach 1:
The sealing tabs are designed with a curved geometry that naturally follows the aerodynamic stream. This curvature is built into the tab design, allowing it to bend smoothly under pressure and maintain contact with the sealing surface. The curved shape simplifies the manufacturing process compared to complex variable geometry, while still achieving the desired sealing performance.
3Loss of energy
If the second sealing tab contacts the first sealing tab to dynamically seal the gap, then air leakage is reduced, but wear may occur at the contact point between tabs
Solution Approach 1:
The air pressure differential itself acts as an intermediary force that activates the sealing mechanism. The pressure differential causes the flexible tabs to bend and contact each other, creating a dynamic seal without requiring additional actuating mechanisms. This self-activating approach reduces mechanical complexity and potential failure points.
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
This solution effectively minimizes air leaks between the sealing plates, improving the sealing efficiency and reducing air re-injection into the turbine stream, thereby enhancing the overall performance and reducing wear on the sealing components.
Implementation Method 1
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 tab and the second sealing tab are curved in a mounting position respectively in the first internal groove and in the second internal groove and have a bending degree of freedom starting from their mounting position in the presence of an air pressure
Data Source
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), linked by linked by sealing tabs (21, 22) in the wall (11) and in the flange (12). The invention is characterised in that the grooves (31, 32) and tabs (21, 22) are curved, the tabs (21, 22) having a bending degree of freedom starting from their mounting position in the presence of an air pressure exerted from upstream to downstream between the adjacent connection faces (13a, 13b) of the at least two adjacent ring sectors (10) during operation of the turbine, the tab (22) having a second point (220) which is in contact with a point (213) of the tab (21).