Fans
When customers choose cooling fans, most of them only pay attention to the common parameters such as current, voltage, power, air volume, wind speed, speed and noise, and rarely ask about the parameters of the fan blades, and generally only ask about the number of blades. However, the parameters of the fan blades have an important impact on the air volume, wind speed, noise, etc. of the fan. Here I would like to share with you a few important fan blade parameters on the impact of fan performance.
1: Blade curvature
Within a certain range, the greater the curvature of the blade, the greater the kinetic energy of the gas at the same speed, that is, the greater the air volume and wind pressure. At the same time, the greater the resistance of the blades, the greater the torque required of the motor.
2: Blade inclination
The larger the inclination angle, the greater the pressure difference between the upper and lower surfaces of the blade, and the greater the wind pressure at the same speed. However, excessive pressure on the upper surface may cause backflow and reduce fan performance. Therefore, the inclination angle of the fan blade should also be increased within a certain limit.
3: Blade spacing
If the distance between the blades is too small, it will lead to airflow disturbance, increase the friction on the blade surface, and reduce the efficiency of the fan. If the distance between the blades is too large, the pressure loss will increase, and the wind pressure will be insufficient.
4: Number of blades
Regardless of whether the number of blades is more or less, the number of blades of axial fans is often 3, 5, 7, 11 and other odd numbers, which is due to the use of even number of symmetrical fan blades, and the balance is not adjusted, it is easy to resonate the system, if the blade material can not resist the fatigue caused by vibration, the blades or mandrel will be broken, so the odd number of fan blades are mostly used.
5: Blade end gap
How to adjust the gap between the fan blade and the frame is a major problem in fan design. If the gap is too small, the air flow will rub against the blades and outer frame, increasing the noise. Increasing the gap will reduce fan efficiency due to effects such as flyback airflow. The choice is difficult for the designers.
6: Blade curvature
In addition to having a certain curvature on the cross-section, the fan blade does not extend straight along the radial direction in the overhead plane, but is slightly bent in the direction of rotation to form a certain arc. This ensures that the blowing air flow is concentrated in the cylindrical space directly in front of the air outlet, increasing the air supply distance and air pressure.
7: Blade smoothness
This is an indicator that is not influenced by design factors and basically depends on the manufacturer's mold forming and post-processing process. Outside of the design curve, unevenness on the blades can create turbulence during rotation, increase friction, reduce fan efficiency, compromise fan performance, and increase operating noise. The above is a description of the impact of fan blade parameters on performance.
