Today about different frequency noise influence on axial cooling fan

Cooling fan can be seen everywhere, from the large cooling tower, the tunnel ventilation cooling fan, to household cooling fan, oil absorption cooling fan and micro computer cooling fan, cooling is generally used in building large exhaust ventilation fan can be roughly divided into centrifugal fan and axial flow fan, YiRongChuan today to introduce the structure and characteristics of axial flow cooling fan. Axial flow cooling fan support bar as the fixed end, at the end of the fixed end is round gusset plate structure, on the other side of the support bar connected with the cooling fan blade, the cooling fan is generally trapezoidal plate, its surface has a curved surface, surface distortion and wave shaped, makes the cooling fan with oblique and curved shapes. When run axial fan, cooling fan rotation range can cover all of the fan inside edge range, to the fullest so that you can swirl through the gas mask and not leak, and produce more rich, more stable air flow, time of inhaled air volume is bigger. Cooling fan corrugated surface on the shaft wind flow during can promote and guide through the air, make the cooling fan inhaled air flow from the axis wind flow closed to, will not flow to the subsequent rotating fan blade, not only greatly decreasing the running noise, wind resistance and prevent the blade because it increases with the increase of rotational speed. When the cooling fan with equal Angle separately, will appear a series of harmonic resonance phenomenon, and a series of harmonic frequency corresponding to the blade by integer times frequency, the frequency corresponding to the cooling fan revolutions per second and leaf number, the product of the resonance phenomenon will produce noise, may interfere with people's hearing. Despite the discomfort caused by noise is primarily subjective, but there are two factors that can affect the interference of sound: sound pressure level ( The noise intensity) Noise and noise distribution of pitch, so if the tones of distribution which is separated from background noise zone, even strength low noise can be annoying. Provide a used to calculate the axial Angle between cooling blade spacing method, the method in terms of noise, especially on the meaning of the noise, is converted to improve the implementation of the cooling fan type, so that the noise produced by the possible. By calculating the sound intensity at different frequency of the value of integral ( The total noise) Range, in the Angle of the blade cases generated noise approximately equal to the Angle between blade conditions such as noise, however, the noise distribution of different pitch sound comfort level higher.