Propeller Blade Geometry Using Fibonacci Spiral Projection
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Solution Overview
Problem
Conventional propellers face efficiency limitations at high blade pitch angles, especially at zero fluid velocity inflow conditions, leading to stalling and increased power consumption.
Innovation Solution
The propeller blades are designed with a surface geometry defined by projecting a two-dimensional Fibonacci spiral onto a surface of revolution defined by a square hyperbola, allowing for operation at high pitch angles without stalling, with symmetrical or asymmetrical leading and trailing portions, and uniform thickness, which reduces power input and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high blade pitch angle is used to increase thrust efficiency, then thrust generation is improved, but fluid velocity must be sufficiently high to prevent stall
Solution Approach 1:
The propeller blade employs asymmetric pitch distribution along its span, with the root section having a higher pitch angle than the tip section. This asymmetric configuration allows the blade to generate effective thrust at high pitch angles while preventing stall conditions, particularly at zero or low fluid velocities where conventional symmetric propellers would fail
Solution Approach 2:
Different sections of the propeller blade are assigned different pitch angles optimized for their specific location. The root portion uses a higher pitch angle to generate thrust when fluid velocity is low, while the tip portion uses a lower pitch angle to maintain efficiency at higher velocities, creating locally optimized performance throughout the blade span
2Ease of manufacture
If conventional propeller design is used, then manufacturing is simple, but power input is excessive to achieve required thrust
Solution Approach 1:
The invention modifies the pitch angle parameter distribution along the blade span and the rotational speed parameter to optimize performance. By operating at reduced rotational speeds with optimized pitch distribution, the propeller achieves the same thrust output with significantly lower shaft power consumption compared to conventional designs
3Productivity
If high rotational speed is used to compensate for low pitch efficiency, then thrust is maintained, but power consumption increases
Solution Approach 1:
The propeller design enables effective operation across a dynamic range of rotational speeds by optimizing the pitch angle distribution. The asymmetric pitch configuration allows the blade to maintain thrust efficiency at lower rotational speeds where conventional propellers would require excessive power, providing dynamic adaptability to varying operational conditions
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 propeller achieves equivalent thrust at significantly reduced power levels and noise, with improved airflow consistency and reduced drag, demonstrating a 46% increase in efficiency compared to conventional fans.
Implementation Method 1
a propeller that can be operated at high blade pitch angles at zero fluid velocity inflow conditions without stalling
Data Source
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AI summary
A propeller formed along the lines of a vortex, i.e. a Fibonacci spiral projected onto a surface formed by a square hyperbola. Fluid flows evenly along the length of the propeller with less turbulence allowing it to operate at a higher pitch without stalling and resulting in reduced power requirements for a given flow rate. The underlying geometric shape of a vortex is an equiangular logarithmic spiral also known as golden spiral or Fibonacci spiral as is often found in natural objects ranging from sea shells to spiral galaxies. When viewed three dimensionally, the fluid flow in a vortex can be drawn as a projection of a golden spiral onto a surface of revolution of a square hyperbola where the vertex is equal to one and the focus is equal to the square root of 2.