How to reduce the noise level

How to reduce the noise levelBy R&D Dept.

Refer to the heat dissipation of electronic and electric equipments, list below the causes made the noise and the way to reduce it.

1. System impedance
The airflow resistance from the computer systems or equipments is called system impedance. For blow-in system, the total area measure of the air outlet needs to be 20% ~ 40% larger than that of the air intake. As for the blowout system, the total area measure of air intake needs to be 20% ~ 40% larger than that of the air outlet. If the air outlet of blow-in system or the air intake of blow-out system is too small, it brings more system impedance, and consequently poorer heat dissipation. If increasing the fan speed to enlarge the airflow, the noise level will be higher. System impedance can be reduced and the noise level will be lowered at the same time from proper adjustment of the area measure of air intake and air outlet, and also do proper arrangement of the system’s components.

But, if the air outlet of blow-in system is too big, or the air intake of blow-out system is too big, the airflow speed will be too low. Thus, it is unable to bring out the heat of part components, nor to work effective dissipation. The bigger space inside the system makes the smaller flow impedance. The heat dissipation is better if the heat source components located on the way of airflow.

2. Flow turbulence
The vertical barrier and sharp angle shapes in the passage of airflow will cause noise. Therefore, we need to prevent from vertical obstacle or angle shape, particularly on the crucial air intake and outlet areas where having higher air speed. GLOBEFAN DC fan, DC blower got curve-edged design on the air intake and outlet to minimize the flow turbulence enabling to accelerate the airflow blowing in and out.

3. Fan speed and size
The fan with high speed makes higher noise level than that with low speed. Thus, it is recommended to use the fan with low speed if possible. With the same airflow, the fan in bigger size and lower speed is quieter than that in smaller size and higher speed.

4. Temperature rise
Within a system, the airflow required from cooling is with inverse ratio against allowable temperature rise. Slight temperature rise reduces airflow tremendously. Thus, if lower slightly the limit of allowable temperature rise, the airflow is lowered and the noise level is reduced significantly.

5. Fan fixing components
Components design of fan fixing relates to the system noise level. Thus, it’s essential to selects anti-vibration materials while fix the fan or assembly the fan on your chassis. If special low noise design is required, please contact our sales department.