Gas Turbine Shroud With Undulating Tangs for Stator Vane Support
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Solution Overview
Problem
Conventional shroud manufacturing in gas turbine engines is labor-intensive, costly, and results in inconsistent material thickness, leading to vibrations and inefficiencies due to inadequate support and sealing of stator vanes.
Innovation Solution
A shroud design featuring an arcuate base with inclined flanges and undulating tangs that engage with stator vanes for a firm interference fit, using a manufacturing method that involves forming a metal sheet to create a uniform thickness and reduce material waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional forging and machining methods are used to manufacture the shroud, then the shroud can be produced with high strength, but the manufacturing process is labor-intensive, costly, and results in inconsistent material thickness
Solution Approach 1:
The patent changes the manufacturing parameters from conventional forging and machining to a specialized forming process that produces consistent material thickness. The shroud is formed with a uniform thickness of approximately 0.063 inches throughout, eliminating the variability inherent in traditional methods while maintaining structural integrity through controlled forming parameters.
Solution Approach 2:
The shroud is divided into multiple segments that are formed separately and then assembled together using interference fits. This segmentation allows each segment to be manufactured with consistent thickness and quality control, while the overall shroud assembly achieves the required strength through the combined segments and their interlocking joints.
2Ease of manufacture
If conventional machining is used to produce shroud segments, then the shroud can be manufactured, but a major portion of material is removed and converted to scrap metal chips
Solution Approach 1:
The manufacturing process parameters are changed from subtractive machining to formative shaping. The shroud segments are formed directly to their final shape and dimensions through a forming process that adds material to a mandrel or mold, eliminating the need to remove large portions of material and converting the process from material-removing to material-efficient.
Solution Approach 2:
The conventional mechanical machining system that removes material is replaced with a forming system that shapes material. The forming process uses controlled deformation and shaping mechanisms to create the shroud segments, substituting the material-removing machining operation with a material-conserving forming operation.
3Ease of manufacture
If conventional design of the shroud is used, then the shroud can be manufactured, but the stator vanes are not firmly supported, resulting in vibrations in the gas turbine engine
Solution Approach 1:
The tangs are given a curved, arcuate shape that conforms to the rotational motion and centrifugal forces within the engine. This curvature allows the tangs to flex and adapt to operational stresses while maintaining firm contact with the stator vanes, providing stable support that reduces vibrations compared to straight, rigid tang designs.
Solution Approach 2:
The shroud design incorporates dynamic characteristics through the curved tangs that can flex and adapt during engine operation. The tangs are designed to move and adjust slightly under centrifugal force and thermal expansion, maintaining optimal contact with the stator vanes throughout the operational range, thereby providing consistent vibration reduction.
4Quantity of substance
If conventional manufacturing techniques are used, then the shroud can be produced, but complex machine tools and rough machining processes are required
Solution Approach 1:
The manufacturing parameters are changed to use simpler forming equipment instead of complex machining tools. The forming process uses controlled deformation and shaping operations that can be performed with less sophisticated equipment, reducing the complexity of machine tools required while efficiently utilizing the material to create the shroud segments.
Data Source
AI summary
A shroud for a gas turbine engine, the shroud including: an arcuate base extending circumferentially about a central axis; a pair of opposing flanges extending from respective axial ends of the arcuate base; and a pair of tangs spaced apart from the arcuate base and extending towards each other. Moreover, the arcuate base, the pair of flanges, and the pair of tangs define a slot. Each tang defines a width extending from the respective flange and a thickness 10 orthogonal to the width. Each tang includes an undulating pattern extending along a whole of the thickness and at least a portion of the width. The undulating pattern of each tang is configured to at least partially engage with the complementary mating features of the plurality of stator vanes. Further, a method of manufacturing the shroud by using a metal sheet is disclosed.