Segmented Tip Shroud Alignment Features
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Solution Overview
Problem
In rotary machines, tip shrouds fail to align properly, leading to increased leakage of compressed working fluid, reduced blade life, and higher maintenance costs due to creep or yield, and potential debris introduction into the gas path.
Innovation Solution
A device and method featuring complementary alignment features on tip shrouds that nest radially, axially, and circumferentially to enhance sealing and prevent overlapping, allowing for larger tip shrouds without compromising blade life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tip shrouds are used to reduce leakage of compressed working fluid, then sealing performance is improved, but tip shrouds increase mass at the blade tip which increases creep or yield and reduces blade life
Solution Approach 1:
The tip shroud is divided into multiple segments that can be independently positioned and aligned. Each segment has alignment features that ensure proper positioning, allowing the shroud to achieve effective sealing while distributing the mass and stress more effectively across multiple smaller components rather than a single large mass at the blade tip.
2Reliability
If tip shroud size is increased to improve sealing, then leakage reduction is improved, but tip shroud mass increases which increases creep or yield and reduces blade life
Solution Approach 1:
The tip shroud is segmented into multiple smaller components that collectively provide the sealing function. This segmentation allows the sealing surface area to be increased for better leakage prevention while the individual segment masses remain lower, reducing the overall impact on blade tip mass and associated creep or yield issues.
Solution Approach 2:
The alignment features extend in multiple dimensions (radial, axial, and circumferential) to provide precise positioning of the tip shroud segments. This multi-dimensional alignment allows for optimized sealing geometry without requiring excessive mass, as the positioning is achieved through geometric constraints rather than increased material volume.
3Productivity
If tip shrouds are used to reduce leakage, then rotary machine efficiency is improved, but misalignment may occur leading to overlapping or debris introduction
Solution Approach 1:
Complementary alignment features are designed with nested geometries where features on adjacent tip shroud segments fit together like nested dolls. This nesting arrangement provides self-aligning capability that ensures precise radial, axial, and circumferential positioning, preventing misalignment and overlapping while maintaining high sealing efficiency for optimal rotary machine performance.
Solution Approach 2:
The complementary alignment features are designed to automatically self-align the tip shroud segments during assembly or operation. The nested geometric features guide the segments into their correct positions without requiring external alignment tools or procedures, ensuring precise alignment and preventing overlapping or debris introduction while maintaining high sealing efficiency.
Data Source
AI summary
A device for aligning tip shrouds includes a platform configured to connect to a blade, a first projection that extends circumferentially across at least a portion of the platform, and a first complementary alignment feature on the first projection. A method for aligning tip shrouds includes rotating a plurality of tip shrouds, wherein each tip shroud is coupled to a blade, and aligning adjacent tip shrouds by nesting a first alignment feature of a first tip shroud into a second alignment feature of a second tip shroud.