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ZAWARD Thermal Technology Insights
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Cooling fan, a commodity product in thermal solution, has various options subject to function, noise level, and appearance. The fan noise level, a major sound source, has always been the focus in the thermal industry. In this issue, we will guide you through causes of fan noise, solutions, how the noise level is measured.
Cause and solution
At the start, let’s dig into details of the cause, factors that cause fan noise and the solution, how to reduce the noise level.
* Flow turbulence
Vertical barriers and sharp angle shapes in the passage of airflow causes noise, which is flow turbulence, particularly the area of air intake and outlet where have higher airspeed. Avoiding the vertical obstacle and angle shape is the solution to the problem. ZAWARD’S fan blades are designed with curve shapes to minimize the flow turbulence and accelerate the airflow in and out.
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*System impedance
System impedance is the airflow resistance from computer systems or equipment. For the blow-in system, the total area measure of the air outlet needs to be 20~40% larger than the air intake and vice versa for blow-out system of the air intake. The smaller the system area is, the more system impedance it brings, resulting in poorer heat-dissipation. Increasing fan speed to boost airflow causes a higher noise level. Proper adjustment of the area measure of air intake and outlet and the arrangement of system components can effectively reduce system impedance and lower noise level. Consequently, if the system area is too big, the airflow will be too low for sufficient heat-dissipation, thus, the components of heat source should be positioned on the passage of airflow.
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*Fan speed and size
The higher the fan speed is, the louder the noise becomes. Hence, it’s recommended to use the fan with low speed if possible. With the same airflow, bigger fan size and lower speed are much quieter than the ones in smaller size and higher speed.
*Fan fixing components
Accessories for fan assembling affect the system noise level as well. Anti-vibration materials are essential when it comes to assembling fans on chassis.
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Acoustic measurement
After realizing the causes of fan noise and solutions to it. We continue to how the sound is being measured.
Sound pressure level (SPL) is a logarithmic measure of the effective pressure of a sound relative to a reference value. The sound pressure level is measured in an anechoic chamber, a free-field constructed as all surfaces are built with sound and absorbing materials, ensuring the only sound is attributed to the noise source. The setting is to position the microphone one meter from the air intake of the testing fan. In ZAWARD’s anechoic chamber, all testing conditions conduct strictly with the ISO7779 standard.
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Ultra-quiet fan
Low noise is the “trademark” of ZAWARD’s fan, particularly the Golf fan series. Its low flow turbulence of perfect 3-dimension impeller shapes and low flow resistance dimples surface design make quieter rotating and more effective
heat-dissipation.
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ZAWARD has the ability to design the fan, for different needs, we are looking forward to having the opportunity to develop new products with you.
For more product details, please feel free to visit our website. Any inquiries of thermal solutions are welcome. If you have any questions, please contact us.
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With best regards,
ZAWARD CORPORATION
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Carmen Chen/ Managing Director
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