Turbine Blade Tip Shroud with Angled Fin and Platform
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Solution Overview
Problem
Existing turbine blade designs for heavy-duty gas turbines face challenges in achieving optimal performance in terms of vibration damping, lightweight construction, and minimizing over-tip leakage flow, especially in end-stage blades where centrifugal forces are highest.
Innovation Solution
A turbine blade design featuring a tip shroud with a fin and platform structure, where the fin extends at an angle across the tip end of the blade, and the platform portions are strategically positioned to enhance stiffness and reduce leakage, incorporating variable thickness and additional platform features to minimize material usage and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a traditional tip shroud design is used, then the blade structure is simple, but the structural strength and stiffness are insufficient, especially in end-stage turbine blades where centrifugal forces are highest
Solution Approach 1:
The tip shroud is segmented into distinct functional components: a fin portion extending from the blade tip and a platform portion connecting to adjacent blades. This segmentation allows each component to be optimized independently - the fin provides stiffness against centrifugal forces while the platform reduces leakage flow, resolving the contradiction between strength and complexity
Solution Approach 2:
The tip shroud design adds a third dimension by extending the fin outward from the blade tip surface and creating a platform that connects laterally to adjacent blades. This dimensional expansion transforms a simple cap structure into a three-dimensional framework that provides enhanced structural strength and stiffness without excessive complexity
2Strength
If more material is used in the tip shroud to increase stiffness and strength, then the structural performance improves, but the amount of material that has to pass through the narrow blade space in the mould during casting increases
Solution Approach 1:
The tip shroud employs local quality by concentrating material where it is most needed - the fin portion has optimized thickness and geometry to provide maximum stiffness per unit mass, while the platform portion is strategically shaped to reduce leakage flow. This localized material distribution achieves high stiffness with minimal material quantity, resolving the contradiction between strength and material usage
Solution Approach 2:
The design optimizes geometric parameters of the tip shroud, including fin thickness, platform dimensions, and overall shape, to achieve the minimum material quantity required for sufficient stiffness. By carefully tuning these parameters, the design minimizes material volume while maintaining structural integrity, addressing the contradiction between stiffness and material quantity
3Loss of energy
If the fin extends further across the tip end to reduce leakage, then the leakage flow is minimized, but the amount of material in the tip shroud increases
Solution Approach 1:
The leakage reduction function is segmented between the fin portion and the platform portion. The fin extends partway across the tip end to block leakage flow, while the platform connects to adjacent blades to seal the remaining gap. This segmentation allows effective leakage control without requiring the fin to extend fully across the entire tip width, minimizing material usage while reducing energy loss
Data Source
AI summary
A blade includes a leading edge, a trailing edge, a pressure surface, a suction surface, a root end, a tip end, a tip shroud attached to the tip end, the tip shroud comprising a platform and a fin, wherein the fin having a leading edge side facing towards the leading edge of the blade, a trailing edge side facing towards the trailing edge of the blade, a back end and a front end, the leading edge side and the trailing edge side extending between the back end and the front end, the fin extending across the tip end of the blade at an angle to the chord of the blade at the tip end of the blade. A first platform portion extends from the leading edge side of the fin to the suction surface. A second platform portion extends from the trailing edge side of the fin to the pressure surface at the tip end of the blade.