Propeller Blade Cone Geometry for Axial Thrust
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Solution Overview
Problem
Conventional helicoidal propellers generate significant turbulence relative to the thrust they produce, and existing modifications, such as conical propellers, suffer from inefficiencies due to radial fluid flow rather than axial thrust direction.
Innovation Solution
The propeller blades are shaped to conform to a cone surface with a blade center axis aligned with the cone's generator line, where the hub is fixed at the root, and the leading edge is positioned forward of the trailing edge, allowing the axis of rotation to intersect the cone at a distance that optimizes structural strength and reduces turbulence by directing fluid flow axially.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conical propeller blades are designed with large circumferential span (about 135° at the root) and faces angled toward the axis of rotation, then the blade structure can be strengthened, but fluid flow is directed radially inward rather than axially away from the thrust surface, resulting in large inefficiencies
Solution Approach 1:
The patent changes the geometric parameters of the propeller blades by defining them as conforming to a cone surface with specific angular relationships. The blade center axis corresponds to a generator line of the cone, and the hub axis intersects the generator line at a specific distance from the cone's vertex. These parameter changes optimize the balance between structural strength and propulsion efficiency by directing fluid flow axially away from the thrust surface rather than radially inward.
2Force
If helicoidal propeller blades are used to generate thrust, then propulsion force is produced, but a large amount of turbulence is created relative to the thrust generated
Solution Approach 1:
The patent applies curvature by designing propeller blades that conform to the surface of a cone rather than using traditional helicoidal (screw-like) shapes. This conical curvature optimizes the fluid flow patterns around the blades, reducing turbulence while maintaining thrust generation. The specific geometric relationship where the blade center axis corresponds to a generator line of the cone creates more efficient flow characteristics compared to conventional helicoidal designs.
3Strength
If the axis of rotation intersects the generator line at a distance of at least half the length of the distance from the blade root to tip, then structural strength is optimized, but the blade subtends a smaller circumference of the reference cone
Solution Approach 1:
The patent optimizes the intersection distance parameter between the hub axis and the generator line, positioning it at a distance of at least half the length of the distance from the blade root to tip along the generator line. This parameter optimization achieves a balance where the blade subtends a manageable portion of the reference cone circumference (90° or less, more preferably 45° or less) while maintaining optimal structural strength and fluid flow characteristics.
Data Source
AI summary
The blades of the propeller are characterized by a blade center axis which corresponds to a generator line of a cone to which the blade, or blade thrust surface, conforms. The propeller hub is fixed to the blade at the root, in line with the blade center axis, such that the hub axis and blade center axis lie in the same plane, and the leading edge of the blade is positioned forward (referring to the upstream direction of movement caused by the propeller) of the trailing edge of the blade.