Why does the explosion-proof and anti-corrosion fan have noise?


Explosion-proof and anti-corrosion fanIt is a kind of exhaust fan. It has the characteristics of good performance, good high temperature resistance, etc., has a smaller footprint than a centrifugal fan, and is easy to install. Therefore, it has been widely selected in many industries. However, after using it for a period of time, we will find that the exhaust fan has unexpected noise problems. Why is this?
When the blades of the smoke exhaust fan are thin and sweep forward too much, and the center of gravity is deviated from the center of the root part of the blade, the airflow is easily stimulated by the centrifugal force caused by the higher speed and the change of the blade lift caused by the instability of the intake air. The blade vibrates. At the same time, due to fluid-solid coupling, it may also cause the exhaust fan blades to gallop, which will lead to early fatigue and damage of the blades, reduce the fan's freeze rate, and produce greater impact. Aerodynamic noise.

Secondly, it is also related to the vibration frequency of the blades of the exhaust fan. The low-frequency vibration shape of the blade is mainly determined by the overall torsion of the blade, while the high frequency is mainly determined by the bending wave of the blade. From the point of view of the effect on noise, it is believed that the shape of the first six-order mode has a greater impact, because its swing has a greater impact on the flow field, resulting in a change in the angle of attack. The blade entrance, thus forming a wave in the surface lift of the blade, this wave is more serious. This situation will cause gallop, generate a lot of aerodynamic noise and greatly reduce the conclusion rate.
In order to reduce the occurrence of this situation, when using explosion-proof and anti-corrosion fans, you must rely on the correct use of the smoke exhaust fan instructions.

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