Noise reduction measures of cooling tower condenser and specific analysis of noise sources
Author：Trlon Views: Time:2020-11-25
The noise generated by the cooling tower during normal operation includes splashing water noise, fan noise, motor noise, circulating water pump noise, and water pipeline vibration radiation noise. Among them, the splashing noise of the cooling tower, fan noise, and motor noise are the main noise sources. How to control the noise of the cooling tower condenser? What are the specific noise reduction measures. The editor of trlon, a Guangdong cooling tower manufacturer, will give you a detailed introduction based on the actual case of RT-Mart supermarket.
Analysis on Noise Source of Cooling Tower Condenser
1. Splashing noise
: Splashing noise is produced by two different noise mechanisms: one is the sharp impulse noise emitted when a water drop hits the water surface; the other is the noise radiated by the volume pulsation of the bubble generated by the water drop.
Due to the high drop height of the cooling tower, the splash speed and kinetic energy of the water droplets are high, which results in high splash noise. Splashing noise radiates outward as a surface sound source, and the noise attenuates as the propagation distance increases. Splashing noise becomes a noise source of factory boundary noise.
2. Fan noise
: Fan noise is aerodynamic noise, including rotating noise and turbulence noise. Rotating noise is the gas pressure pulsation noise caused by periodically hitting the air when the fan blades rotate; turbulence noise is mainly the noise generated by the air attached to the blades continuously slipping into vortexes when the fan blades rotate.
The fan noise of the cooling tower is mainly turbulence noise. Since the diameter of the fan impeller of the cooling tower of this project is greater than 4m, the linear velocity of the fan impeller tip is relatively large, so the noise is relatively large. Due to conditions, the on-site measurement could not be carried out (the measurement needs to be carried out at 45° above the cooling tower fan). Estimated according to relevant experience, the noise should be around 86dB(A). Fan noise presents low-frequency characteristics, and the airflow water content is high, which makes it difficult to manage. In addition, the cooling tower fan is located on the top of the cooling tower, and the noise of the fan has a greater impact on the noise in the distance than in the vicinity.
3. Motor noise
: Fans and water pumps need to be equipped with motors. Motor noise mainly includes rotating noise caused by poor dynamic balance of the rotor, electromagnetic noise caused by the cutting magnetic field of the rotor, aerodynamic noise of the cooling fan, and machinery generated by bearing friction. Noise etc.
The motor of the fan is installed in the open air at the bottom of the fan barrel of the cooling tower, and the noise a measured 1m away from it is as large as 87.2dB(A).
In view of the noise principle and characteristics of the on-site unit, our company provides a complete set of noise reduction measures in order to achieve a good governance effect
Noise reduction measures for condenser units
1. Sound barrier design
Taking into account the factors such as the existing fan port and height, the treatment effect, etc., the static source "Yusheng" full-frequency sound absorption and insulation board is used to set up tongue and mouth sound absorption and insulation barriers on all sides of the condenser unit, so that the air inlet and outlet of the condenser equipment are not affected. The impact, considering that the bottom of the anti-typhoon barrier requires a reinforced concrete foundation (concrete foundation with existing equipment can be used). The barrier height is 4 meters, of which the bottom 1 meter non-absorption sound insulation screen is used as the condenser air inlet channel, and the total length is 58 meters.
Taking into account the high position of the barrier and the high height of the barrier, the oblique support of the barrier is made on the inside of the barrier to make the barrier meet the wind pressure requirements of the 12th typhoon.
2. Muffler design
Taking into account the impact of condenser fan noise on high floors, an exhaust muffler is added at the condenser air outlet, and a static source "Yusheng" full-frequency muffler insert is placed on the inside of the barrier. The insert thickness is 100mm, and the interval between the sheets is 120mm. The size of the insert is 2500*1180mm, totaling 100 pieces, and the noise reduction is 10-15 decibels.
The above is the specific analysis of the cooling tower condenser noise source and specific noise reduction measures of the cooling tower manufacturer trlon editor. After our treatment, the condenser noise has reached the environmental protection requirements and the noise emission limit requirements, and the daytime noise value is ≤ 60dB(A), the noise value at night ≤50dB(A), which improves the noise environment outside residential buildings and allows residents in the community to have a better life experience.