Fan Blade Wing-Flap Geometry for Stalling Prevention
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Solution Overview
Problem
Conventional fans experience reduced airflow efficiency and increased noise due to the stalling phenomenon, which occurs when the attack-angle exceeds a critical value, leading to vortex generation and inefficient energy consumption.
Innovation Solution
The fan design incorporates rotor or stationary blades with a wing part and a flap part forming a predetermined angle, where the ratio of the axial length of the flap part to the axial length of the blade is less than 0.75, preventing stalling and enhancing airflow efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the rotating speed of the fan is raised to increase airflow, then the airflow speed increases, but the attack-angle exceeds the critical angle causing stalling phenomenon and vortex generation, which reduces airflow efficiency and increases noise
Solution Approach 1:
The patent changes the geometric parameters of the blades by introducing a flap part that forms a predetermined angle with the wing part. This structural parameter modification allows the blade to maintain optimal attack angles across different rotating speeds, preventing stalling phenomenon and vortex generation while enabling increased airflow speed and efficiency
2Speed
If the rotating speed of the fan is raised to increase airflow, then the airflow speed increases, but the stalling phenomenon generates noises and wastes energy consumption
Solution Approach 1:
By modifying the blade geometry with a flap part forming a predetermined angle with the wing part, the patent changes the aerodynamic parameters to prevent vortex generation and stalling. This eliminates the harmful noise and energy waste associated with stalling while maintaining high airflow speeds
3Productivity
If the attack-angle is increased to improve airflow efficiency, then the airflow efficiency improves, but the attack-angle exceeds the critical angle causing stalling phenomenon
Solution Approach 1:
The patent introduces a flap part with a predetermined angle relative to the wing part, which fundamentally changes the attack angle parameters. This geometric modification allows the blade to operate at higher effective attack angles without exceeding the critical stalling angle, thereby improving airflow efficiency while maintaining stable, vortex-free airflow
Solution Approach 2:
The flap part creates a dynamic aerodynamic structure that adapts to different operating conditions. As the blade rotates at different speeds, the flap configuration maintains optimal attack angles, preventing the airflow from separating and stalling, thus ensuring both high efficiency and stable operation across varying 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
This design enhances airflow efficiency, delays stalling, and reduces noise, achieving better performance with the same power consumption and noise levels compared to conventional fans, with airflow efficiency increased by more than 5% as shown in test results.
Implementation Method 1
Each rotor blade has a wing part and a flap part, and the wing part and the flap part form a predetermined angle
Implementation Method 2
Once the attack-angle α exceeds a critical angle, the airflow is separated from the surface of each blade 122, and a vortex is generated above each blade 122
Data Source
AI summary
A fan includes a frame and an impeller. The impeller is disposed in the frame and the impeller has a plurality of blades. Each blade has a wing part and a flap part, and the wing part and the flap part form a predetermined angle. A blade is also disclosed.