A cooling fan manufacturer to tell you the source of the noise and the solution
dc blower noise is how come of, small make up to answer questions: total noise level and the blade fan speed is direct ratio six times. According to the analysis, the fan noise basically is the nature of the dipole. Can launch further, noise is due to the blade with fluctuating force acting on the air flow through the fan. Can think fan discrete frequency noise source has two, one is with the movement of the stress field caused by rotor blades of the propeller noise, another is the aerodynamic interference caused by pulse noise power. The distance between the wind motor, stator blade is one of the important factors of interference noise.
when the distance is very small, can influence the change of flow and wake, leaves may also be as sound barriers, and strengthen the adjacent leaf blade of the lift on the pulse of sound radiation. This effect depends on the acoustic wavelength associated with the lift pulsation to as barrier leaf size. In the frequency range of the ratio is greater than 2, due to the influence of the change of the radiation intensity is the most significant. So when a radiation noise of the upstream and downstream of blades have the same leaf number, and each of the two columns of leaf blade at the same time meet with a rotor blade and the source of both sides constitute the sound barrier, the effect will be better.
when the distance between the dynamic and static blades increases, the decrease of the bit stream interference effect is much faster than the effect of changes in the rate of wake blade as the role of sound barrier will decrease with the increase of distance. Thus, there are at least three parameters affect the magnitude of interference noise: velocity waveforms of blade shape ( Is the blade load) , the distance between the blade columns, and as a source of radiation area of leaf. Very small distance between two acoustic effects may be produced. If built on rotor in interference field of force ripple make moving blade a sound source, and static blades is sound barrier.
. Now you know why general fan fan noise? Cooling fan manufacturer tong chi focus on production research and development of all kinds of fan fan, if necessary, welcome to inquire. Gucci is your best procurement business.