Professional acoustic engineers should design and select noise reduction products (damping suction and sound insulation modules, air inlet sound attenuating louvers, exhaust mufflers, acoustic insulation doors, steel structures, etc.) according to the spatial location relationship between noise sources (cooling towers) and sensitive points (noise exceeding the standard points) and relevant national standards (or Party A's specific requirements).
The principle of noise control of cooling tower is to carry out noise control work without affecting the normal operation of cooling tower. Therefore, the basic requirement is that the effective air inlet and exhaust area of the noise reduction facility shall not be less than the exhaust area of the original cooling tower, and the total pressure loss of the cooling tower inlet and exhaust air silencing facilities shall not be greater than 100pa.
OneAnalysis of cooling tower noise sources
The noise sources of cooling towers mainly include aerodynamic noise, mechanical noise and overboard noise of fans. The main characteristics of the noise sources of the cooling tower are as follows:
1) The sound level noise value at the outlet of the fan at the mouth of the axial fan reaches 80-85db(a), which is due to the turbulence of the air in the diversion pipe at the top of the cooling tower and the pressure disturbance caused by friction, and the interaction between the propeller and the air produces vibration and radiation noise. Therefore, it is preliminarily determined that the aerodynamic noise of the fan is the main sound source
2) The mechanical noise of the fan is mainly due to the imbalance of the rotating parts of the fan, which causes the structure to vibrate, which causes the radiation noise on the surface of the tower. Due to the installation of shock absorbers between the fan bracket and the tower body, mechanical noise is not the main factor;
3) The intensity of the impact noise generated by the circulating water of the cooling tower falling freely into the downspout through the packing layer is proportional to the square of the falling water. The measured results show that the sound level noise level of the falling water reaches 70-75dB(a), which is one of the noise sources that need to be treated in the cooling tower.
IICooling tower noise abatement solutions
Scenario 1: The noise source (cooling tower) is higher than the sensitive point (noise exceeding the punctuation point) and the straight-line distance is not less than 30m
Brief description of the scheme:In scenario 1, you can use the sound absorption module (or sound barrier) to build a sound absorption wall around the cooling tower. However, the sound insulation volume of the sound absorption and insulation module (or sound barrier) shall not be less than 35db, and the noise reduction coefficient shall not be less than 085, and the tongue and groove seal must be used between the module and the module. to meet the noise reduction requirements.
Scenario 2: The noise source (cooling tower) is lower than the sensitive point (noise exceeding the punctuation point) and the straight-line distance is less than 30m
Brief description of the scheme:The following technical measures can be used in scenario 2:
Calculate the air inlet and exhaust air volume required by cooling towers and other equipment, and determine the effective air inlet and exhaust area and the effective silencer length of the muffler according to the noise reduction requirements
According to the requirements of noise reduction and noise reduction, determine the thickness and structure of the sound insulation maintenance structure.