Why Does The 3C Smoke Exhaust Axial Flow Fan Produce Noise?

The fire smoke exhaust axial flow fan is a different type of smoke exhaust fan, which has good performance, good high-temperature resistance, high conclusion rate, less footprint than centrifugal fans, and convenient installation. Therefore, it is widely chosen by many industries. But after using it for a period of time, we will find that the fire exhaust fan inexplicably causes noise problems. Why?
When the blades of the fire exhaust fan are thin and excessively swept forward, and the center of gravity deviates from the center of the blade root section, the centrifugal force caused by higher rotational speed and the changes in blade lift caused by unstable inlet airflow can easily trigger blade vibration. At the same time, due to fluid structure coupling, it may also cause flutter of the blades of the fire exhaust fan, leading to premature fatigue damage of the blades, reducing the conclusion rate of the fan, and generating significant aerodynamic noise.
Secondly, it is also related to the vibration mode frequency of the blades of the fire exhaust fan. The low-frequency vibration mode of the blade is mainly characterized by the overall twisting and swinging of the blade, while the high-frequency vibration mode is mainly characterized by the bending wave of the blade. From the perspective of its impact on noise, it is believed that the first six vibration modes have a significant impact, as their oscillation has a significant impact on the flow field, causing changes in the blade inlet angle of attack, resulting in fluctuations in blade surface lift. In severe cases, galloping may occur, resulting in atmospheric dynamic noise and a significant decrease in conclusion rate.
In order to reduce the occurrence of this situation, we should use the fire smoke exhaust axial flow fan correctly and ensure the reliable service life of the fire smoke exhaust fan.