Main causes of noise generated by axial flow fans

Axial fans and centrifugal fans are commonly used, but there are also some problems in their use. Like axial flow fans, noise can be generated during use. What is the cause of the noise?
When the blade of an axial flow fan is relatively thin and the center of gravity deviates from the center of the blade section, the centrifugal force caused by high speed and the blade lift force changes caused by unstable intake flow can easily stimulate blade vibration. At the same time, due to fixed flow coupling, it may also lead to blade vibration, leading to premature fatigue damage to the blades, reducing fan efficiency, and generating greater aerodynamic noise.
The modal vibration form of the impeller is mainly composed of different circumferential vibrations of four blades. This is mainly due to the fact that the stiffness of the front blade is much lower than that of the hub, i.e., the stiffness of the blade is "soft" while the hub is "hard"; The low-frequency vibration type of the blade is mainly the overall torsional oscillation of the blade, while the high-frequency vibration type is mainly the bending wave of the blade. From the perspective of the impact of noise, the impact of the first six steps of vibration is greater, because its swing has a greater impact on the flow field, resulting in changes in the blade inlet attack angle, resulting in fluctuations in the blade surface lift. In severe cases, vibration can occur, generating a large amount of aerodynamic noise, and reducing efficiency.
To understand the causes of noise generated by axial flow fans, attention should be paid to reducing noise generation during use.
The above is the main reason why axial flow fans generate noise summarized by Suzhou Yonghecheng Fan Industry Co., Ltd. For any related knowledge that you do not understand, you can consult us