Conical Propeller Blade Geometry for Lower Turbulence Thrust
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Solution Overview
Problem
Helicoidal propellers generate significant turbulence and inefficiencies due to fluid flow directed radially inward, rather than axially away from the thrust surface, leading to reduced thrust efficiency.
Innovation Solution
Conical propellers with blades shaped to conform to the surface of a cone, where the hub axis and blade center axis lie in the same plane, and the leading edge is positioned forward of the trailing edge, with the blade subtending 90° or less of the reference cone circumference, and the axis of rotation intersecting the generator line at a distance of at least half the length from the blade root to tip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If helicoidal propeller blades are used, then thrust is generated, but turbulence is significantly increased and efficiency is reduced due to radial inward fluid flow
Solution Approach 1:
The patent changes the geometric parameters of the propeller blades by conforming them to a conical surface rather than a helicoidal surface. This parameter change in blade geometry fundamentally alters the fluid flow pattern from radial inward to axial downstream, resolving the contradiction between thrust generation and turbulence reduction
Solution Approach 2:
The patent applies curvature by shaping blades to conform to a conical surface with specific radius of curvature. This curvature design ensures that the blade faces are not angled toward the axis of rotation, preventing radial inward flow and reducing turbulence while maintaining thrust efficiency
2Area of stationary object
If propeller blades span a large circumference (about 135° at the root), then more thrust surface area is provided, but inefficiencies increase as fluid flow is directed radially inward
Solution Approach 1:
The patent changes the angular span parameter of the blades, reducing them to subtend 90° or less of the reference cone circumference. This parameter change maintains sufficient thrust surface area while reorienting the blade geometry to prevent radial inward flow, thereby reducing energy loss
3Strength
If blade faces are angled toward the axis of rotation, then structural support is provided, but large inefficiencies occur as fluid flow is directed radially inward rather than axially away
Solution Approach 1:
The patent changes the angular orientation parameter of the blade faces by conforming them to a conical surface where the faces are not angled toward the axis of rotation. This parameter change redirects fluid flow axially away from the thrust surface, improving thrust efficiency while maintaining structural support through the conical geometry
Solution Approach 2:
The patent transitions from a two-dimensional planar blade face orientation to a three-dimensional conical surface configuration. This dimensional change allows the blade faces to be supported by the conical structure while directing fluid flow axially, resolving the contradiction between structural support and thrust efficiency
Data Source
AI summary
A propeller. 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.