| With the improvement of people's living standard,more and more people pay attention to the habitation and noise pollution.The noise of cooling tower is one of important noise fountainhead in power plant.The noise of some cooling towers nearby the residential place has affected residents' daily life,so reducing of noise of cooling tower has very strong realistic meaning.Wet-style natural-ventilation cooling tower is regarded as the research object in the paper,and we set up the mathematical model of the noise's producing and diffusing in rain area of cooling tower,and the main parametric variables include draining water content,height of air inlet and so on.We also set up the mathematical model of noise attenuation exterior of cooling tower in engineering.Leading broads are used for reducing the cooling tower noise in the paper as a new way.We get the distribution of noise interior and exterior of cooling tower by numerical simulation studied with Fluent.The cooling tower of 300MW thermal power is regarded as an example in this paper. At first,we get the noise distribution without leading broad and air inlet by simulation studied.Secondly,when we use the leading broads,we get the noise distribution when the amount and fixing angle of leading broad is different.Furthermore,the author measured the noise distribution in power plant.As we know from the calculation,the noise distribution of cooling tower is a circle when there is no air inlet and no leading broad.The centre of the circle is the centre of cooling tower,and the radius is radial distance.With the increasing of the height,the noise increase,and it matches practical case.Considering air inlet,the noise distribution of cooling tower is out of regularity.The noise is high where the wind is concentrated, and the noise increases first then decreases at height direction as the speed of air inlet increases.When install the leading broads,the noise is almost unchanged when there is no air inlet;when we consider air inlet,the air in rain area forms vortex flow because of the using of leading broads.The noise distribution of cooling tower accords to the wind distribution,and the noise is high at outlet of cooling tower.When the amount of leading broads is 36 and the speed of air inlet is 3m/s or 6m/s,we compare the noise level when the angle of fixing broad is 30,45,60and90.There is almost no noise lower when angle is 90 and the noise decreases when the angle is 30,45 and 60.The installation of leading board changed the octave noise in the frequency of the distribution, but also to achieve the purpose of the noise decreasing.When the fixing angle of leading broads is 30,we get the noise distribution in different amount.The amount of the broad is 12,36,90 respectively.Compared the noise distribution,that the amount of the broad is 90 has best effect,36 next,and 12 has west effect.So the effect can be greater as the amount of broad increases.We also calculate the amount of wind in order to reflect whether the broad affects the economy of cooling tower.Compared the calculation results,we find that the amount of wind which broad is used gets more.The amount of inlet wind increases with the increase of fixing angle of broad and the amount of inlet wind increases with the increase of wind speed.When the amount of broad is 12,36,90 respectively,the amount of inlet wind increases first and then decreases.So the best way of decreasing noise and the best economical of operation do not happen at the same time.We get some improving ways according to above analysis.The results of the paper afford theory basis for engineering,and we find a new way in decreasing noise of cooling tower. |
