Rotor Blade Recess Geometry for Stable Wind-Driven Torque
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Solution Overview
Problem
Existing rotary blades and rotating devices suffer from inefficiencies in rotation due to fluid flow around the front blade surface leading to resistance and variation in drag, resulting in reduced efficiency and torque variation.
Innovation Solution
The rotary blade design includes a front blade surface with recesses and a rear blade surface with a smaller curvature depth, along with a blade-support portion that guides fluid flow effectively, reducing resistance and enhancing lift generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If fluid flows along the front blade surface and goes around to the rear blade surface area, then the rotary blade can be rotated by drag and lift, but rotation resistance is generated on the following rotary blade
Solution Approach 1:
The patent extracts the harmful fluid flow that wraps around to the rear blade surface by introducing a recess structure on the front blade surface. This recess acts as a flow separator that prevents the fluid from following the blade contour to the rear surface, thereby eliminating the source of rotation resistance on subsequent blades while preserving the beneficial drag and lift forces.
Solution Approach 2:
The patent converts the potentially harmful wrapped fluid flow into a beneficial feature by designing the recess to generate controlled vortices. These vortices enhance the separation of fluid streams, preventing rear surface flow while the recess structure itself generates additional drag force that contributes to rotation torque, thus transforming a harmful effect into a beneficial one.
2Power
If maximum drag is generated when fluid is received by the rear blade surface, then rotation torque is maximized, but variation in drag with respect to rotational position is great
Solution Approach 1:
The patent applies local quality by creating different surface characteristics at different locations on the blade. The recess is positioned specifically on the front blade surface at a location where fluid flow separation naturally occurs, creating a localized modification that generates consistent drag across different rotational positions without requiring the entire blade to be redesigned.
Solution Approach 2:
The recess structure performs preliminary action by pre-separating the fluid flow before it reaches the rear blade surface. This preliminary flow separation ensures that regardless of the blade's rotational position, the fluid is diverted in a controlled manner, maintaining consistent drag characteristics and reducing variation in rotation torque throughout the rotation cycle.
3Object-affected harmful factors
If the recess is formed on the first curved surface, then fluid flow is separated and rotation resistance is reduced, but the structure becomes more complex
Solution Approach 1:
The recess is designed with curved surfaces that follow the natural contour of the blade's first curved surface. By using curvature rather than sharp edges or complex geometries, the design achieves effective flow separation while maintaining a relatively simple manufacturing process. The curved recess integrates smoothly with the existing blade aerodynamics without introducing discontinuities that would complicate fabrication.
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 design improves rotation efficiency by minimizing fluid flow around the rear blade surface and stabilizing drag, resulting in consistent torque and enhanced performance.
Implementation Method 1
The recess formed on the first curved surface can serve as a vortex generator. That is, local fluid stagnation (vortex) is generated at the recess
Implementation Method 2
lift generated by a speed difference between air flows flowing along the first and second curved surfaces of the front blade surface
Implementation Method 3
drag generated when wind is received by the rear blade surface
Data Source
AI summary
This wind power generation device includes a plurality of rotary blades 15 around a rotation axis. Each rotary blade 15 includes a front blade surface 16 parallel to the rotation axis and curved so as to protrude frontward in a rotation direction, and a rear blade surface 17 located on the back side of the front blade surface 16, being parallel to the rotation axis, being curved so as to be concave frontward in the rotation direction, and having a smaller curve depth than the front blade surface 16. The front blade surface 16 includes a first curved surface 19 forming a part far from the rotation axis and formed frontward in the rotation direction from an outer end 21 of the rotary blade 15, and a second curved surface 20 forming a part close to the rotation axis Li and formed rearward in the rotation direction from a crest 18 of the front blade surface 16 so as to connect to an inner end 22, a surface length thereof in a plan view being smaller than that of the first curved surface 19. The first curved surface 19 has recesses 23 at positions closer to the outer end 21 than to the crest 18 of the front blade surface 16. Thus, a rotary blade that rotates by receiving a fluid and can improve rotation efficiency, is provided.