Turbomachine Shroud Vane Welding via Offset Openings
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Solution Overview
Problem
Current methods for attaching stationary vanes to the outer shroud in turbomachines, such as threaded fastening and full-thickness welding, face issues like thread breakage, manufacturing complexity, and aerodynamic disruptions due to weld droplets, leading to increased costs and mechanical defects.
Innovation Solution
A novel assembly method where the outer shroud features offset openings allowing a welded connection along the exterior contour, preventing thermal impact on the inner face and eliminating the need for additional parts like beam stoppers, ensuring a strong and aerodynamically smooth attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If full-thickness welding is used to connect the shroud to the blade tip throughout the material thickness, then the connection solidity is improved, but surface discontinuities and droplet projections are generated on the inner face of the shroud
Solution Approach 1:
The welding process is segmented into two distinct phases: first welding through the entire thickness to establish strong connection, then performing a second welding pass on the inner face to smooth surface discontinuities. This segmentation resolves the contradiction by addressing both connection solidity and surface quality in separate sequential operations.
Solution Approach 2:
The harmful surface discontinuities and droplet projections generated by full-thickness welding are converted into a benefit by using them as attachment points for a wire that fills these irregularities. The wire is welded to the inner face, flowing into and smoothing the surface defects, thereby eliminating aerodynamic disruptions while maintaining connection strength.
2Strength
If threaded rod and bolt assemblies are used to attach stationary vanes to the outer shroud, then the connection solidity is improved, but the device complexity and manufacturing costs increase
Solution Approach 1:
The complex threaded rod and bolt assembly components are extracted and replaced with a simpler direct welding solution. The invention removes the need for separate fastening elements by integrating the attachment function directly into the welding process between the blade tip and shroud, thereby reducing device complexity while maintaining connection solidity.
Solution Approach 2:
The attachment function that previously required separate threaded rods and nuts is merged into a single welding operation. The welding process simultaneously creates both the structural connection and the aerodynamic surface finish, eliminating the need for multiple separate components and assembly steps.
3Strength
If full-thickness welding is performed to ensure connection solidity, then the attachment strength is improved, but aerodynamic performance deteriorates due to surface discontinuities
Solution Approach 1:
The welding process is segmented into two distinct phases: first welding through the entire thickness to establish strong connection, then performing a second welding pass on the inner face to smooth surface discontinuities. This segmentation resolves the contradiction by addressing both connection solidity and surface quality in separate sequential operations.
Solution Approach 2:
The harmful surface discontinuities and droplet projections generated by full-thickness welding are converted into a benefit by using them as attachment points for a wire that fills these irregularities. The wire is welded to the inner face, flowing into and smoothing the surface defects, thereby eliminating aerodynamic disruptions while maintaining connection strength.
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 provides a reliable, cost-effective, and aerodynamically efficient attachment of vanes to the outer shroud, avoiding bead and droplet formation, ensuring precise positioning and reducing manufacturing complexities.
Implementation Method 1
The invention also relates to the mounting method by welding between an outer shroud and the tip of at least one fixed vane
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to an assembly for a rectifier stage of a turbomachine, comprising: - an outer shell (5) having a series of openings (51) for mounting each blade (6) fixed by welding between the edge of an opening (51) and the contour of the platform (621) of the blade, the contour of the outer section (51a) of an opening (51) surrounding, in radial projection, the contour of the inner section (51b), the shell (5) not comprising any other drilling, and - at least one fixed blade (6) the top of which has an unperforated platform (621) received in one of said openings (51) prior to the welding step so that an inner face of the platform (621) is in contact with a bearing face (51c) of the shell (5), the contour of the platform (621) having a shape identical to that of the contour of the opening (51). Application to the rectifier stage of an axial compressor or a turbomachine turbine.