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The Axial Fan's Noise Anaiysis And Maintenance

Dongyang Exploit Trade Co.,Ltd | Updated: Dec 06, 2017

Noise analysis

   The total fan noise level and blade speed is proportional to the sixth power.  According to the analysis, fans noiseThe source is basically dipole-like.  Further to be introduced, the noise is due to the action of the blades

on the air pulsating power flowing through the fan.  It can be considered that there are two discrete frequency noise sources for the wind turbine, one is the propeller noise caused by the pressure field of the rotor blades and the other is the pulsation noise caused by the aerodynamic interference.  Wind motor, the distance between the static blades is an important factor in interference noise.

   When this distance is small, changes in the bit stream and the wake will have an effect. The blade may also serve as an acoustic barrier to enhance sound radiation generated by lift pulsations on the blades of adjacent blade rows.  The effect depends on the ratio of the acoustic wavelength associated with lift pulsation to the blade size as a barrier.  In the frequency range where the ratio is greater than 2, the change in radiation intensity due to this effect is most noticeable.  So this effect will be stronger when a radiated noise vane has the same number of vanes upstream and downstream, and each of the two vanes encounters a rotor blade at the same time, forming a sound barrier on either side of the source.When the distance between the moving and stationary vanes increases and the influence of the interference of the bit stream is much faster than that of the wake velocity, 

   The effect of the blade as the sound barrier also decreases with the increase of the distance.  Thus, there are at least three parameters that affect the magnitude of the interference noise: the blade shape of the velocity field waveform (ie, the blade load), the distance between the blade rows, and the  radiant area of the blade as the sound source.  Very small pitches can have two acoustic effects.  If the stationary blade interference field in the moving blade to establish the force of the pulsation of the leaflet into a sound source, while the static leafis the sound barrier.

maintenance

1, the use of the environment should always be kept clean,FanKeep the surface clean, inlet and outlet should not have debris, regularly remove the fan and pipe dust and other debris.

2. Only operate when the fan is completely normal. At the same time, ensure sufficient capacity of power supply facilities, stable voltage and no defect operation. The power supply lines must be dedicated lines and should not

be powered by temporary lines for a long time.

3, the fans found in thecourse of abnormal fan noise, the motor serious fever, shell charged, switch tripping, can not start and so on, should immediately stop checking.  In order to ensure the safety, it is not allowed to carry on the maintenance in the running of the fan. After overhauling, the running should be carried out for about 5 minutes to confirm that there is no abnormal phenomenon and then turn on the machine.

4, according to the use of environmental conditions from time to time to replace or replace the bearing grease(motor sealed bearings do not have to change during the service life of grease), in order to ensure good fanlubrication during operation, the number of refueling not less than 1000 hours / Times closed bearings and  Motor bearings, Refueling ZL-3 lithium-based grease filled bearing inner and outer rings 1/3;

5, the fan should be stored in a dry environment, to avoid damp motor.  Fans in the open storage, there should be defensive measures.  In the process of storage and handling should prevent fan bump, so as to avoid damage to the fan.