Turbine Vane Root Sealing via Mechanical Tenon
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Solution Overview
Problem
The existing methods for attaching a calibrating plate to the vane root in turbine engines, such as brazing or autogenous welding, are costly and risk crack formation, which can lead to leaks and compromise the thermal behavior and service life of the turbine vanes.
Innovation Solution
A mechanical sealing mechanism using a tenon and mortise connection between the calibrating plate and the vane root, preventing air circulation between channels without welding or brazing, ensuring effective sealing and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If brazing is used to attach the calibrating plate to the vane root, then sealing between channels is ensured, but manufacturing cost increases and crack formation risk arises
Solution Approach 1:
The sealing function is segmented from the attachment function. The calibrating plate is attached to the vane root through a simplified connection method (screws, clips, or adhesive), while sealing is achieved through separate sealing elements (gaskets, sealing rings, or sealing layers) positioned between the plate and vane root. This segmentation allows each function to be optimized independently, reducing manufacturing complexity and cost while maintaining reliable sealing.
2Reliability
If brazing is used to attach the calibrating plate to the vane root, then sealing between channels is ensured, but crack formation risk increases
Solution Approach 1:
The sealing function is separated from the attachment function. The calibrating plate is attached using methods that do not induce thermal stress (screws, clips, or adhesive), while sealing is achieved through separate sealing elements. This prevents the thermal cycling and stress concentration that lead to crack formation in brazed joints, particularly around small diameter apertures.
Solution Approach 2:
A sealing element (gasket, sealing ring, or sealing layer) acts as an intermediary between the calibrating plate and the vane root. This intermediary provides the sealing function without requiring direct thermal bonding, thereby eliminating the crack formation risk associated with brazing while maintaining effective channel separation.
3Ease of manufacture
If autogenous welding is used to attach the calibrating plate, then manufacturing cost is reduced, but sealing effectiveness is compromised
Solution Approach 1:
The attachment function (achieved through inexpensive autogenous welding or other simple connection methods) is segmented from the sealing function (achieved through separate sealing elements). This allows the use of low-cost attachment methods without compromising sealing effectiveness, as the sealing is provided by dedicated sealing components rather than relying on the weld itself.
4Manufacturing precision
If small diameter apertures are used in the calibrating plate, then flow control precision is improved, but brazing blockage risk increases
Solution Approach 1:
The attachment process is segmented from the sealing process. Since sealing is achieved through separate sealing elements rather than brazing, small diameter apertures can be used in the calibrating plate without risk of brazing material blocking the openings. This enables precise flow control through small apertures while eliminating the manufacturing reliability issue associated with brazing over such small features.
Data Source
AI summary
The invention relates to a movable vane of a turbomachine comprising a blade (12) with inner cooling cavities and a root (11) by which means the vane can be mounted on a rotor disk, the root comprising at least two channels (11a) communicating with said inner cavities and leading to the base (11b) thereof, said base comprising at least two openings (11b1, 11b2) through which the channels open up, and a calibrating plate (20) provided with calibrated perforations (21, 22) corresponding to said openings being attached to the base (11b) of the root. The vane is characterized in that a mechanical means (25, 26; 11m1, 11m2) forming a sealing barrier between the two openings is arranged between the plate and the base of the root.