Is it true that the lower the noise level, the better the fan?

Axial-flow fan When operating normally, all machines generate a certain amount of noise. Research shows that when wind speeds exceed... 0.75 Rice / Noise is generated within seconds. The lower the wind speed, the quieter the noise. As fan technology continues to advance, we can reduce noise pollution more and more. When choosing a fan, is it always better to go for one with lower noise levels? While maintaining low noise is certainly desirable, we also need to take economic factors into account. The lower the required noise level, the higher the cost of the fan. For every reduction in noise... 10 dB The cost of the fan would then double (empirical observation, non-linear). The noise level of most fans cannot be lower than... 35 Decibels. Therefore, when choosing a fan, there’s no need to strive for ultra-low noise—just aim for a reasonable level that’s acceptable.

Axial-flow fan It is typically used in scenarios with low pressure requirements and high flow demands, and it also generates noise during operation. This noise is essentially dipole in nature, making noise control for axial-flow fans particularly important. Current control methods mainly include: :

1. In terms of aerodynamic performance, efforts should be made to minimize airflow impact and boundary-layer separation in order to avoid or reduce the occurrence of impact noise and vortex noise. In the design, sharp protrusions and abrupt bends in the flow passages should be avoided.

2. Based on the principle of acoustic impedance mismatch, installing silencers at the inlet and outlet of an axial-flow fan can reduce the sound radiation noise at these locations, thereby effectively lowering the overall noise level.

3. By in Axial-flow fan Installing sound-absorbing panels at the pipe outlet can effectively reduce noise levels.

4. To prevent or reduce the propagation of noise from axial-flow fans, the fans are recently placed in soundproof rooms with sound-absorbing properties.

5. A common method for blade modification is blade perforation. This approach can reduce vortex noise and allow air resistance to pass through smoothly. Blade perforation is typically applied to working impeller blades, as vortex separation frequently occurs at the blade outlet. By introducing perforations, a portion of the airflow can bypass from the high-pressure side of the blade to its low-pressure side. As a result, the separation point on the blade can shift downward, reducing the separation area in the blade’s outlet region and significantly lowering noise levels.