Segmented Turbine Blade Design for Loss Reduction
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Solution Overview
Problem
Steam turbines face efficiency losses and thermal stress issues due to high temperatures, which affect their operational flexibility and part-load performance, particularly at higher aspect ratios where existing blade designs result in profile, secondary, and leakage losses.
Innovation Solution
The turbine blade design features a root section with a first curved section, a tip section with a second curved section, and mean sections with a prismatic shape, providing reduced axial width and a more constant blade outlet angle, which reduces profile and secondary losses while increasing lift and thermal resilience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional prismatic blade design is used, then manufacturing and orientation standardization are simplified, but profile losses and secondary losses increase, reducing efficiency
Solution Approach 1:
The blade is divided into distinct sections: a root section with a first curved section, a tip section with a second curved section, and multiple mean sections with a prismatic shape positioned between them. This segmentation allows different portions of the blade to have optimized geometries for their specific functional requirements, reducing overall energy losses while maintaining manufacturability.
Solution Approach 2:
Different sections of the blade are given different geometric characteristics: the root and tip sections have curved sections for optimal flow control and reduced secondary losses, while the mean sections have prismatic shapes for structural efficiency and standardized manufacturing. This local optimization of geometry reduces profile losses without requiring the entire blade to be complex.
2Productivity
If blade aspect ratio is increased to improve efficiency, then more stages can be accommodated, but thermal stresses and hot spots increase due to higher temperatures
Solution Approach 1:
The root section features a first curved section and the tip section features a second curved section. These curved geometries improve steam flow characteristics and reduce turbulence, allowing for better thermal distribution across the blade. This reduces hot spots and thermal stresses while maintaining the ability to operate at higher aspect ratios for improved efficiency.
3Loss of energy
If blade geometry is optimized for reduced losses, then efficiency improves, but manufacturing complexity and retrofitting difficulty increase
Solution Approach 1:
By dividing the blade into standardized prismatic mean sections and curved root/tip sections, the design allows for modular manufacturing. The mean sections can be produced using standardized processes, while the curved sections are limited to specific regions, making the overall blade more manufacturable than a fully custom geometry while still achieving reduced leakage and mixing losses.
Solution Approach 2:
The blade design optimizes specific geometric parameters such as the curvature radius of the root and tip sections, the axial width of mean sections, and the positioning of prismatic sections. These parameter optimizations reduce leakage and mixing losses while maintaining a geometry that can be manufactured using conventional techniques, facilitating easier retrofitting.
Data Source
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AI summary
The present application provides a turbine blade (300). The turbine blade includes a root section (215) with a first curved section (310), a tip section (220) with a second curved section (320), and number of mean sections (225) positioned between the root section (215) and the tip section (220). The mean sections (225) each include a substantially prismatic shape (330).