Twisted Ceiling Fan Blade with Graduated Dihedral
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Solution Overview
Problem
Conventional ceiling fans with flat blades do not efficiently distribute air throughout a room, as they primarily direct airflow downwardly, and their design assumptions, such as constant airflow velocity and angle of attack from root to tip, are invalid for ceiling fans, leading to inadequate air circulation in ambient spaces.
Innovation Solution
The ceiling fan blades are designed with a non-uniform twist, increasing the angle of attack from the root to the tip, with a greater angle distal to the axis than proximal, to optimize airflow distribution, featuring a 26-inch blade with two airflow sections having different twist rates, ensuring a continuous arch that enhances air dissemination both directly under and around the fan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fan blades are designed with conventional flat shape and uniform angle of attack, then manufacturing is simple, but airflow distribution is inadequate and primarily downward
Solution Approach 1:
The blade is designed with non-uniform geometry where different sections have different characteristics. The blade features a curved planform with varying chord length and thickness distribution along the span, allowing each section to optimize local airflow conditions while maintaining overall circulation efficiency
Solution Approach 2:
The blade employs curved surfaces and arcs in its geometry, including a curved planform shape with rounded leading and trailing edges. The blade cross-section varies along the span with curved airfoil profiles, creating smooth airflow paths that enhance circulation and distribute air more evenly throughout the room
2Device complexity
If fan blades direct airflow primarily downward, then the design is simple, but air circulation in ambient spaces is inadequate
Solution Approach 1:
The blade design extends airflow control beyond the vertical downward direction by utilizing the blade's curved planform and angled geometry to redirect air in multiple directions. The blade's orientation and curvature create horizontal and radial airflow components in addition to vertical motion, achieving three-dimensional air circulation that distributes air throughout the ambient space rather than just downward
3Speed
If fan blade tip travels much faster than root end, then rotation dynamics are natural, but wind resistance load is unbalanced
Solution Approach 1:
The blade features varying chord length and cross-sectional properties along its span to compensate for the speed difference between root and tip. The chord length typically decreases toward the tip, and the airfoil thickness and camber are adjusted locally to balance the aerodynamic loads, ensuring that faster-moving tip sections experience proportionally less resistance per unit area
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 significantly improves air distribution throughout the room, providing a wider and more even airflow, addressing the limitations of prior art by increasing airflow efficiency and coverage beyond the direct downward direction.
Implementation Method 1
the blades having a greater angle of attack distal the fan axis than proximally the fan axis... This causes air to be driven downwardly
Data Source
AI summary
A ceiling fan blade is disclosed that is twisted rather than flat and has a graduated dihedral. The dihedral is provided for a wider distribution of divergence of air in the space beneath the fan. The blade (10) is demarked to have three sections which include a mounting section (11) and two airflow sections (12) and (13). The two airflow sections (12) and (13) are twisted with the rate of twist from the root end to the tip end being nonuniform. The twist or ratio of the degree increase in the angle of attack over each inch in length deceases from root end to the tip end.