Counter-Rotating Axial Air Moving Device with Variable Pitch Rear Rotor
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Solution Overview
Problem
Thin type counter-rotating axial air moving devices face performance degradation due to high back pressure, leading to increased rotation speed, vibration, noise, and energy consumption.
Innovation Solution
A counter-rotating axial air moving device structure with a rear rotor having gradually increasing pitch angles from the inner to the outer side, stacked with a front rotor to maintain a thickness-to-diameter ratio between 0.25 and 0.8, enhancing static pressure versus airflow rate performance without increasing rotation speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the pitch angle of blades decreases gradually from inner side to outer side (conventional design), then the blade structure can be simplified, but the device cannot withstand high back pressure and performance is significantly reduced
Solution Approach 1:
The patent inverts the conventional pitch angle distribution by making the pitch angle increase from the inner side to the outer side of the blade, rather than decreasing. This inversion allows the thin-type counter-rotating axial air moving device to withstand high back pressure while maintaining good performance characteristics, resolving the contradiction between structural simplicity and back pressure resistance.
2Productivity
If the rotation speed is increased to compensate for performance reduction, then the air flowrate can be maintained, but vibration and noise deteriorate and energy consumption increases
Solution Approach 1:
The patent changes the pitch angle parameter distribution along the blade radius, making it increase from inner to outer side. This parameter change improves the static pressure versus air flowrate performance curve, allowing the device to maintain required air flowrate without increasing rotation speed, thus controlling energy consumption and avoiding vibration and noise deterioration.
3Reliability
If the pitch angle of rear rotor blades increases gradually from inner side to outer side, then the static pressure versus air flowrate performance is improved, but the device complexity increases
Solution Approach 1:
The patent applies local quality by creating different pitch angle characteristics in different regions of the blade. The pitch angle increases gradually from the inner side to the outer side, optimizing the aerodynamic performance at each radial position. This local optimization improves the overall performance curve while maintaining a systematic and manufacturable blade configuration.
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 solution maintains performance without deteriorating vibration and noise while controlling energy consumption by optimizing the pitch angle configuration of the rear rotor blades, resulting in improved static pressure and airflow rate at the same rotation speed.
Implementation Method 1
The rear rotor includes a rear hub and a plurality of rear blades arranged on a periphery of the rear hub. A pitch angle of each of the rear blades increases gradually in a direction away from the rear hub.
Data Source
AI summary
A counter rotating axial air moving device structure is disclosed. The rear rotor includes a rear hub and rear blades, and a pitch angle of each of the rear blades increases gradually in a direction away from the rear hub. The front rotor, the rear rotor and the stator component are stacked with each other. The ratio of the thickness to the diameter is equal to or greater than about 0.25 and equal to or less than about 0.8. Therefore, a better performance curve is obtained, and the vibration and noise are avoided.