Tunnel fans inevitably generate noise during operation, including aerodynamic noise and mechanical noise. Among them, aerodynamic noise is the main noise, and its sound pressure level is usually more than 10 decibels higher than mechanical noise. It propagates into the surrounding air through the inlet and outlet of the fan. Due to the fact that the noise of tunnel fans is related to their structural form, air volume, total pressure, and speed, attention should be paid to the above factors when seeking ways and methods to reduce noise. So, how to reduce the noise of fan sound sources?

1. We need to choose the type of tunnel fan reasonably. If high noise is required, then we need to choose a low-noise fan. Under the same air volume and pressure, the centrifugal fan with wing blades has lower noise and the centrifugal fan with front plate blades has higher noise.

The working point of the tunnel fan should be close to the high efficiency point. The higher the efficiency of the same type of fan, the lower the noise. In order to maintain the working point of the fan in the high efficiency zone of the fan, it is necessary to avoid using valves to adjust the working conditions. If valves need to be installed at the fan and extrusion end, a good location is 1 meter away from the fan and outlet. This can reduce noise to below 2000 Hz, and the airflow at the fan inlet should be kept uniform.

3. The airflow velocity inside the pipeline should not be too high to avoid causing noise. The airflow velocity inside the pipeline should be selected according to different requirements and relevant regulations. And we need to pay attention to the transmission methods of tunnel fans and motors. The direct transmission noise of fans is relatively low, followed by couplings. The seamless V-belt transmission is slightly inferior. The fan should be equipped with a low-noise motor.

The above three points are three important ways to reduce the noise of tunnel fans through sound sources. If you have any other questions or concerns about fans, we welcome your call for consultation and look forward to working with you.