Rotary Blade Surface Geometry for Lower Drag Variation
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Solution Overview
Problem
Existing rotary blades and rotating devices suffer from inefficiencies in rotation efficiency due to fluid flow around the blades generating rotation resistance and varying drag across different rotational positions.
Innovation Solution
The rotary blade design includes a front blade surface with a recess to prevent fluid from going around and generating resistance, and a rear blade surface with a slope portion to guide fluid and increase drag, along with a blade-support portion that enhances rigidity and guides fluid effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the rotary blade has a conventional front blade surface and rear blade surface design, then the blade can generate rotation torque through drag and lift, but fluid flows around the blade generating rotation resistance on following blades and causing great variation in drag with rotational position
Solution Approach 1:
The front blade surface is divided into multiple curved surfaces (first curved surface, second curved surface, third curved surface) with different functions. The first curved surface generates lift, the second curved surface controls flow separation, and the third curved surface prevents fluid from reaching the rear blade surface, thereby segmenting the fluid flow paths and eliminating rotation resistance on following blades
Solution Approach 2:
The second curved surface acts as an intermediary element between the first curved surface and the third curved surface. It controls the fluid flow to separate at a predetermined position, preventing direct flow from the front blade surface to the rear blade surface, thus eliminating the harmful effect of rotation resistance while maintaining the torque-generating function
2Power
If the rotary blade receives maximum drag when fluid hits the rear blade surface, then rotation torque is maximized at certain positions, but drag varies greatly with rotational position reducing overall efficiency
Solution Approach 1:
Different portions of the blade are given different qualities: the first curved surface has high curvature for lift generation, the second curved surface has controlled curvature for flow separation, and the third curved surface has specific curvature to block fluid flow. This local differentiation ensures maximum drag is generated at optimal positions while preventing excessive drag variation across rotational positions
Solution Approach 2:
The second curved surface performs preliminary action by causing fluid flow to separate at a predetermined position before the fluid can reach the rear blade surface. This preliminary flow control ensures that drag is generated at the intended location (first curved surface) while preventing unwanted drag variation from fluid hitting the rear surface at various rotational positions
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
This design enhances rotation efficiency by reducing rotation resistance, stabilizing drag across different positions, and improving the overall performance of the rotary blade and rotating device.
Implementation Method 1
lift generated by a speed difference between air flows flowing along the first and second curved surfaces of the front blade surface
Implementation Method 2
drag generated when wind is received by the rear blade surface
Data Source
AI summary
A wind power generation device includes rotary blades that each includes a front blade surface parallel to the rotation axis and curved to protrude frontward, and a rear blade surface, being parallel to the rotation axis, curved so as to be concave frontward, and having a smaller curve depth than the front blade surface. The front blade surface includes a first curved surface far from the rotation axis and formed frontward from an outer end, and a second curved surface close to the rotation axis and formed rearward from a crest to connect to an inner end, a surface length thereof being smaller than that of the first curved surface. The first curved surface has recesses at positions closer to the outer end than to the crest of the front blade surface. Thus, the rotary blade rotates by receiving a fluid and can improve rotation efficiency.