Some common ways to reduce noise in cooling towers

Some common ways to reduce noise in cooling towers

Taking a circular countercurrent cooling tower as an example, the basic principle of its operation is: dry and low enthalpy air enters the cooling tower from the lower part of the cooling tower; high temperature water with high partial pressure of full steam is injected from the upper part of the radiator tube. In the process of water-gas countercurrent, high-temperature water molecules undergo transpiration at the water-gas interface, enter the air from the water phase, and reach the intention of cooling the high-temperature water together.

　 　　 One, cooling tower noise

　　 The noise of cooling tower is dominated by fan noise and falling water noise. Fan noise is the noise that occurs when the fan works, mainly aerodynamic noise, including rotating noise and eddy current noise, as well as the noise of the reducer and the motor driving the fan. The falling water noise is the falling water noise that occurs when the cooling tower falls from the water spraying equipment and colliding with the tower body chassis and the water in the pan. Its value is related to the falling water height and the water flow per unit time, and is generally second only to the fan noise. In addition to the noise mentioned above, there are also the noise of circulating water pumps, equipped motors, and pipe radiation noise.

　　 Cooling tower noise is attenuated according to the line sound source rule; when 1-0, the cooling tower noise is attenuated according to the point sound source rule. According to internship measurement and expert consultation, when the cooling tower is smaller than 2001, in the scale of equivalent diameter, the noise of the cooling tower is non-point source, and the noise level does not change; between 1 equivalent diameter and 2 times equivalent diameter, the noise is in line Sound source attenuation. When the guess point is more than 2 times the equivalent diameter of the cooling tower, the noise will be attenuated according to the point sound source rule. Regarding cooling towers of different types and sizes, 0-0 should be determined based on the internship situation or consulting related experts.

　　 This guessing method is suitable for small cooling towers. According to the negative impact of cooling towers on the environment and countermeasures, this guessing method is suitable for cooling towers in civil buildings.

Because the noise influence of the cooling tower is related to the size of the cooling tower and the distance between the guessing point and the cooling tower, the size of the different guessing method is not very clear. You can consult relevant experts on the selection and scale division of the cooling tower. Definitely.

　　 2. Measures for the prevention and control of cooling tower noise

　　 The noise of the cooling tower affects work and life and brings inconvenience to everyone. There are four main ways to reduce the noise pollution of cooling towers: reasonable planning, reasonable selection of cooling towers, manipulation of transmission paths, and protection of sound receivers.

　　 1. Reasonably plan the placement area

　　Reasonable planning is the completion of functional partitions and dynamic separation. The cooling tower should be placed in an area with low noise requirements, such as a cost area or an active area, because of the strong noise source. Avoid getting too close to noise-sensitive buildings such as offices, dormitories, and residential areas, which may affect the work of employees and residents. Set noise protection distances between different functional areas, and place buildings or rooms with relatively low noise requirements near the noise source side in functional areas with higher environmental noise.

　　2, reasonable selection of cooling towers

　　 There are many types of cooling towers, low-noise cooling towers and ultra-low-noise cooling towers emerge in endlessly. The noise sources of cooling towers mainly include fan noise, water pump noise, and falling water noise. The basis for reducing noise is the shock absorption methods of various mechanical equipment, such as shock-absorbing pads and shock-absorbing springs, to avoid equipment vibration noise. Secondly, a muffler is installed at the inlet and outlet of the cooling tower fan. The effective muffler can reduce the tuyere noise at the mercy of 10dB. In addition, water-permeable materials such as metal mesh, polyurethane, etc. can be installed on the tower chassis, and the falling water height can be reduced. The can also reduce the noise of water pumps and fans through the equipment frequency converter

　　 Under the condition of satisfactory wind exchange coefficient, install the cooling tower outer cover of sound insulation equipment on the outside of the cooling tower. Under normal circumstances, the sound insulation method can reach the effect of 156dB.

　　3, control the transmission path

　　 Manipulating the transmission path means adopting methods from the sound wave transmission path to reduce the transmission energy of the sound wave. The principle is: when sound waves encounter obstacles, reflections, diffractions, etc. will occur, reducing the energy of sound waves received by the outer sound body. You can use natural shelters, or set up sound barriers, green belts, etc. to reduce the impact of noise. When there is no way to circumvent the sensitive point, a protective approach should be adopted for the sensitive point. Noise sensitive points are generally residences, hospitals, schools, government agencies, etc. Regarding noise sensitive points, sound insulation windows and indoor sound-absorbing materials can be installed to reduce the impact of people on the sound at sensitive points.

　　 When purchasing, try to choose low-noise or ultra-low noise cooling towers to reduce or reduce noise.