Turbomachine Blade Elliptical Cross-Section Curvature
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Solution Overview
Problem
Turbomachines face inefficiencies due to abrupt changes in curvature and pressure profiles, leading to flow detachment and thermal stress, which affect the performance and longevity of blades.
Innovation Solution
Designing blades with an outer surface that forms a closed curve along an ellipse or approximately along an ellipse, with continuous curvature and specific detachment points, reducing curvature jumps and material accumulation, thereby smoothing pressure profiles and distributing material uniformly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the outer surface of the blade follows a conventional design, then the manufacturing is simpler, but abrupt changes in curvature occur leading to flow detachment and reduced efficiency
Solution Approach 1:
The outer surface of the blade is designed to follow an elliptical curve in cross-section instead of conventional straight or simple curved lines. This continuous curvature eliminates abrupt changes in the flow path, preventing flow detachment and improving turbomachine efficiency while maintaining manufacturability through standardized geometric forms.
2Strength
If material is accumulated in certain areas of the blade, then structural strength is improved, but thermal stress increases and efficiency decreases
Solution Approach 1:
The blade cross-section is designed with an elliptical outer surface that distributes material uniformly without localized accumulation. This eliminates regions of high thermal stress concentration while maintaining overall structural strength through optimized geometric distribution of material throughout the blade cross-section.
3Ease of manufacture
If the blade cross-section has abrupt curvature changes, then manufacturing is easier, but pressure profile changes abruptly causing flow detachment
Solution Approach 1:
The blade cross-section employs an elliptical outer surface that provides continuous, smooth curvature transitions throughout the entire perimeter. This eliminates abrupt curvature changes that cause flow detachment, ensuring reliable flow attachment while the elliptical geometry remains straightforward to manufacture using standard machining or molding processes.
4Adaptability or versatility
If the outer surface follows a non-elliptical curve, then design flexibility is higher, but curvature jumps occur causing pressure profile disruptions
Solution Approach 1:
The elliptical outer surface provides a mathematically defined continuous curve that eliminates curvature jumps and pressure profile disruptions. The ellipse offers sufficient design flexibility through adjustable aspect ratios and orientations to accommodate various blade requirements while maintaining smooth, uninterrupted curvature that stabilizes the pressure profile throughout the blade cross-section.
Data Source
Figure 1
Figure 2~3
AI summary
A blade (10) for a turbomachine is disclosed. In at least one cross-section orthogonal to a blade longitudinal axis, an outer surface of the blade forms a curve (Γ) which runs continuously along an at least approximate ellipse (E) on the upstream side between a first separation point (P1) and a second separation point (P2). On the pressure side 12, the curve (Γ) has an inflection point W. The distance of the second separation point (P2) from the inflection point W along the curve is at least as large, at least twice as large, at least three times as large, or even at least five times as large as the distance of the second separation point (P2) from the first separation point (P1) along the at least approximate ellipse (E). A blade ring with at least one such blade and a turbomachine are also disclosed.