Mixed-Loading Airfoil Design for Turbomachinery Pressure Loss Reduction
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Solution Overview
Problem
Current turbomachinery airfoil designs face challenges in reducing total pressure loss due to inadequate understanding of boundary layer interactions and limitations in achieving high-lift performance without increasing secondary losses or flow separation.
Innovation Solution
A high-lift airfoil design incorporating a mixed-loading convention that combines aft-loading and front-loading conventions, with varying curvature distributions along its span, to optimize boundary layer behavior and minimize interactions between airfoil and endwall boundary layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-lift airfoils are used to increase loading, then the Zweifel load coefficient increases, but airfoil flow separation and boundary layer thickening occur
Solution Approach 1:
The patent applies different loading conventions to different sections of the airfoil span. The inboard section uses a first loading convention while the outboard section uses a second loading convention, creating locally optimized flow characteristics that prevent separation while maintaining high overall loading.
Solution Approach 2:
The airfoil span is divided into distinct sections (inboard and outboard) with different loading characteristics. This segmentation allows each section to be optimized independently, preventing the flow separation that would occur in a uniform high-lift design.
2Power
If high-lift airfoils are used to increase loading, then the Zweifel load coefficient increases, but secondary losses increase
Solution Approach 1:
Different loading conventions are applied to different spanwise locations to locally optimize the balance between loading and secondary loss. The inboard section uses one convention while the outboard section uses another, creating a gradient that reduces secondary losses while maintaining high loading.
Solution Approach 2:
The patent changes the loading convention parameter along the span of the airfoil. By transitioning from a first loading convention in the inboard section to a second loading convention in the outboard section, the design optimizes the trade-off between loading and secondary losses.
3Area of stationary object
If airfoils are repositioned to meet design requirements, then the working medium fluid area is adjusted, but total pressure loss is not reduced
Solution Approach 1:
Instead of uniformly repositioning airfoils, the patent applies different loading conventions to different sections of the airfoil span. This local optimization reduces total pressure loss by addressing the root cause - the loading distribution - rather than just adjusting geometry.
Solution Approach 2:
Rather than adjusting airfoil position to achieve design requirements, the patent inverts the approach by optimizing the loading convention distribution along the span, which then enables meeting design requirements with reduced pressure loss.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The mixed-loading airfoil design achieves a Zweifel load coefficient greater than 1.2 without flow separation or increased secondary losses, offering improved total pressure loss characteristics by balancing profile and secondary losses across the airfoil span.
Implementation Method 1
the behavior of the boundary layer along the airfoil surface, the behavior of the boundary layers along the inner and outer diameter end walls to which the airfoil is attached
Implementation Method 2
a distribution of fluid pressure, or a pressure loading, over its surfaces. This distribution is highly dependent on the motion of the fluid near the airfoil surface
Data Source
Figure 1
Figure 2A~2D
Figure 3A~3B
AI summary
A high-lift airfoil (10) embodying a combination of loading conventions in a single design specifically to reduce and control total pressure losses that occur in the flow channels between airfoils (10) employed in turbomachinery applications is disclosed herein. The mixed-loading high-lift airfoil designs embody and exhibit the best total profile and secondary loss characteristics possessed by both aft-loaded airfoil and front-loaded airfoil conventions through controlling the development and interaction of boundary layers forming along the surfaces of the airfoils and the endwalls in such applications. The mixed-loading high-lift airfoil may be utilized in both rotating and non-rotating turbomachinery applications. The airfoil comprises a root section (12) comprising a first loading convention, a midspan section (14) comprising a second loading convention, a tip section (16) comprising a third loading convention, wherein a spanwise distribution of said first loading convention, said second loading convention and said third loading convention across a span of said airfoil comprises a mixed-loading convention and a Zweifel load coefficient equal to about or greater than about 1.2.