自然通风逆流湿式冷却塔噪音的传播规律及降噪研究
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摘要
随着人们生活水平的提高,人们对于生活环境的要求越来越高,噪音污染也逐渐受到人们的重视。在电厂中,噪音也成为重要的污染源之一,冷却塔淋水噪音成为重要的噪音源,由于有些电厂的位置比较特殊,冷却塔距离居民区较近,冷却塔噪音已经严重的影响了居民的日常生活,因此冷却塔降噪有很强的现实意义。
在目前冷却塔降噪研究的基础上,本文以自然通风逆流湿式冷却塔为研究对象,建立了以淋水量和进风口高度等为主要参变量的雨区噪音产生和传播的数学模型,亦建立了工程实际中冷却塔外部区域噪音的衰减模型。并且采用了新的降噪方法——导风板降噪,并利用数值模拟的方法模拟了各种情况下冷却塔雨区及外部区域的噪音分布情况。
本文以某300MW火电机组的冷却塔为例,首先对无导风板情况下无侧风和进风速度分别为中、高风速时的冷却塔噪音传播进行了数值计算;又对冷却塔加导风板后,不同的导风板数量和安装角度在风速为零、中、高风速工况下进行了数值计算,得到了不同工况下的噪音分布值。此外,作者还现场实地测量了冷却塔的噪音分布情况。
计算表明,无导风板情况下,当无侧风时,冷却塔噪音传播形成了以冷却塔的中心为圆心,冷却塔径向距离为半径的圆状分布,冷却塔的噪音沿径向分布比较均匀;沿高度方向,随着高度增加,冷却塔的噪音值有所增加,这些与实际测量的情况基本一致。当有侧风时,冷却塔的噪音传播分布不规律,在风比较集中的地方噪音也较集中,而且随着风速的增加,沿高度方向的冷却塔噪音值先增大后减小。
冷却塔的周向加导风板后,无侧风时几乎对噪音分布没有影响;有侧风时,由于导风板对于进风的引导作用和出风的阻挡作用,在冷却塔的雨区形成了漩涡流,噪音沿进风的传播方向分布。冷却塔整个雨区噪音分布不均匀,在出风口处噪音集中,噪音值较高。36块导风板时,对导风板角度分别为30、45、60、90度进风速度分别为中风速和高风速的情况下噪音值的分布进行模拟,90度角时噪音值和无导风板时几乎一致,其余安装角度下噪音值出现了降低。此外导风板的安装改变了倍频程噪音在各频率段的分布情况,也实现了降噪的目的。
在导风板角度同为30度时,对导风板的数量为12、36、90时的噪音分布进行比较,90块板时降噪效果最好,12块板时最差,36块板时居中,说明随着导风板数量增加,降噪效果明显。
本文为了反映冷却塔在加导风板后是否对冷却塔运行的经济性产生影响,作者取进风量作为衡量标准,对不同情况下的进风量进行简单计算。通过对计算结果的比较,加导风板后所有情况的进风量大于未加导风板时的通风量;随着导风板安装角度的增加进风量增加;随着进风速度的增加,进风量增加。不同的导风板数量时,数量依次为12、36、90时,进风量先增大后减小。说明降噪最佳和运行经济性的最佳二者不可兼得。
针对以上分析,本文初步提出了一些改进措施。本课题的研究成果对冷却塔降噪的研究提供了理论依据,并对工程实际中的冷却塔的降噪提供了新思路。
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.
在目前冷却塔降噪研究的基础上,本文以自然通风逆流湿式冷却塔为研究对象,建立了以淋水量和进风口高度等为主要参变量的雨区噪音产生和传播的数学模型,亦建立了工程实际中冷却塔外部区域噪音的衰减模型。并且采用了新的降噪方法——导风板降噪,并利用数值模拟的方法模拟了各种情况下冷却塔雨区及外部区域的噪音分布情况。
本文以某300MW火电机组的冷却塔为例,首先对无导风板情况下无侧风和进风速度分别为中、高风速时的冷却塔噪音传播进行了数值计算;又对冷却塔加导风板后,不同的导风板数量和安装角度在风速为零、中、高风速工况下进行了数值计算,得到了不同工况下的噪音分布值。此外,作者还现场实地测量了冷却塔的噪音分布情况。
计算表明,无导风板情况下,当无侧风时,冷却塔噪音传播形成了以冷却塔的中心为圆心,冷却塔径向距离为半径的圆状分布,冷却塔的噪音沿径向分布比较均匀;沿高度方向,随着高度增加,冷却塔的噪音值有所增加,这些与实际测量的情况基本一致。当有侧风时,冷却塔的噪音传播分布不规律,在风比较集中的地方噪音也较集中,而且随着风速的增加,沿高度方向的冷却塔噪音值先增大后减小。
冷却塔的周向加导风板后,无侧风时几乎对噪音分布没有影响;有侧风时,由于导风板对于进风的引导作用和出风的阻挡作用,在冷却塔的雨区形成了漩涡流,噪音沿进风的传播方向分布。冷却塔整个雨区噪音分布不均匀,在出风口处噪音集中,噪音值较高。36块导风板时,对导风板角度分别为30、45、60、90度进风速度分别为中风速和高风速的情况下噪音值的分布进行模拟,90度角时噪音值和无导风板时几乎一致,其余安装角度下噪音值出现了降低。此外导风板的安装改变了倍频程噪音在各频率段的分布情况,也实现了降噪的目的。
在导风板角度同为30度时,对导风板的数量为12、36、90时的噪音分布进行比较,90块板时降噪效果最好,12块板时最差,36块板时居中,说明随着导风板数量增加,降噪效果明显。
本文为了反映冷却塔在加导风板后是否对冷却塔运行的经济性产生影响,作者取进风量作为衡量标准,对不同情况下的进风量进行简单计算。通过对计算结果的比较,加导风板后所有情况的进风量大于未加导风板时的通风量;随着导风板安装角度的增加进风量增加;随着进风速度的增加,进风量增加。不同的导风板数量时,数量依次为12、36、90时,进风量先增大后减小。说明降噪最佳和运行经济性的最佳二者不可兼得。
针对以上分析,本文初步提出了一些改进措施。本课题的研究成果对冷却塔降噪的研究提供了理论依据,并对工程实际中的冷却塔的降噪提供了新思路。
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.
引文
[1]赵振国.冷却塔.北京:水利水电出版社,1996.
[2]GB 3096-93,城市区域环境噪声标准[s].
[3]马大猷.噪声与振动控制工程手册[M].北京:机械工业出版社,2002.
[4]智乃刚,许亚芬。噪声控制工程的设计与计算,1991.
[5]宫本贤,声屏障隔声量的计算方法与设计.噪声与振动控制,第3期.
[6]倪季良,冷却塔的落水噪声及防治措施的探讨.电力建设,2003年3月第24卷第3期,15-18.
[7]范亚菊,汤征等,火电厂冷却塔噪声治理的计算机模拟,151-152.
[8]倪季良,自然通风冷却塔的噪声污染。工业用水与废水,2001年第5期,4-6。
[9]陈新龙,城市火电厂冷却塔噪声治理.四川电力技术第5期,51-53.
[10]倪季良,冷却塔的落水噪声及其防治措施。工业用水与废水,2003年6月,55-58。
[11]吕玉恒等,特大型双曲线自然通风冷却塔噪声治理.科技纵横,22-24。
[12]毛献忠,陈允文等,逆流式自然通风冷却塔流场及热质交换的数值模拟.计算物理,1994年12月第11卷第2期,384-392.
[13]陈金思,冷却塔减噪综述。安徽化工,2002年第3期,42-43.
[14]胡华,姜学忠,大型双曲线白然通风冷却塔的噪声治理.华东电力,2003年第9期,33-36.
[15]孙建青,徐贤金,谈华,瞿浩,冷却塔噪声及其控制。水利电力劳动保护,1997年6月第2期,21-22。
[16]陈金兴,冷却塔噪声源识别及降噪途径分析.噪声污染与防治,1998年8月,31-32.
[17]赵顺安,廖内平,徐铭,逆流式自然通风冷却塔二维数值模拟优化设计.水利学报,2003年10月,26-31。
[18]徐德林,大型冷却塔噪声综合控制技术.环境工程,2002.12,43-44。
[19]淡洁,冷却塔水滴噪声及其漂浮式降噪装置.水利规划与设计,2006年第4期,55-57.
[20]Krittika Lertsawat,Supichai Tangjaitrong,Prathan Areebhol,Prediction of noise emission from power plantby a mathematical model。 Applied Acoustics 58(1999)469-477.
[21]Kragh J,Anderson B,Jakobsen J.Environmental Noise from Industrial Plants.General Prediction Method.Denmark:Danish Acoustical Laboratory,1982.
[22]G.Bisio~*,G.Rubatto,R.Martini,Heat transfer,energy saving and pollution control in UHP electric-arc furnaces o Energy 25(2000)1047-1066.
[23]Stockmeyer R et al.Einsparung von elektrischer Energie am Lichtbogenofen durch eine neue Ausqualmregelung Stahl a Eisen 1990;110:113-6.
[24]A.M.Kunesch,Water noise in large cooling tower installation。 Noise control vibration isolation,134-137.
[25]Bisio G,Benvenuto G.Possible utilizations of the pressure exergy of natural gas.1n:Proceedings of 28th IECEC,Aug 8-13;Atlanta,GE,vol.2.Washington,DC:American chemical Society,1993:167-73.
[26]Becket L,Hammer,EE.Sidewall and roof panels of a 70 t electric arc furnace with evaporative cooling system.World Steel and Metalworking 1986/87;8:26-32.
[27]Le Louer P,Engler G.Noise control in new electric steelworks,1n:Proceedings of INTER-NOISE 88,30 Aug-1 Sep;Avignon,vol.2,1988:883.
[28]Morris DR,Szargut J.Standard chemical exergy of some elements and compounds on the planet Earth.Energy,1986;11:733-55.
[29]John S.Wang,Prediction and Control of Induced Draft Cooling Tower Noise。Noise control engineering,March-April 1979,74-81.
[30]Walter L.Reinicke,Enno P.Riede,Noise from natural draft cooling tower。Noise control engineering,July-August 1980,28-36.
[31]赵振国,李志悌,石金铃,陈仙松.逆流式自然通风冷却塔通风阻力的研究[J].水动力学研究与进展,1993(4).
[32]王凯,自然通风冷却塔进风口空气动力场的数值模拟与阻力研究[D].山东大学硕士学位论文,2006.
[33]陈东民,自然通风冷却塔内流场与传质传热的数值分析,清华大学硕士学位论文,1994。
[34]朱宪然,电站自然通风湿式冷却塔空气动力场数值模拟,山东大学硕士论文,2002.
[35]王立秋,魏焕彩,周学圣.工程数值分析[M]。济南:山东大学出版社,2002。
[36]孔珑,工程流体力学.北京:中国电力出版社,1998.
[37]吴江航,韩庆书,计算流体力学的理论、方法及应用.北京:科学出版社,1988.
[38]Patankar,S.V.传热和流体流动的数值计算.安徽:安徽科学工业出版社。1984.
[39]赵元宾,基于κ-ξ紊流模型的自然通风湿式冷却塔空气动力场数值模拟.山东大学硕士论文,2005.
[40]李秀云,林万超,冷却塔的节能潜力分析,中国电力,No.10,1997.
[41]债志强,朱克勤,符松,横向风对自然通风干式冷却塔空气流场影响的模型实验研究实验力学,1997.
[42]胡三季,陈玉玲,工业冷却塔与模拟试验塔试验系数的相关关系.
[43]赵顺安,廖内平,徐铭,逆流式自然通风冷却塔二维数值模拟优化设计.
[44]赵振国,石金铃,周常虹,腾新军.冷却塔雨区的热力特性[J].水利学报,2000年第3期。
[45]薛茂,王晓宁,赵晓丹,微穿孔板吸声结构计算及其应用。江苏大学学报,2002年9月。
[46]朱羽中,冷却塔冷却效率评价计算方法.工业用水与废水,2003年12月,61-63。
[2]GB 3096-93,城市区域环境噪声标准[s].
[3]马大猷.噪声与振动控制工程手册[M].北京:机械工业出版社,2002.
[4]智乃刚,许亚芬。噪声控制工程的设计与计算,1991.
[5]宫本贤,声屏障隔声量的计算方法与设计.噪声与振动控制,第3期.
[6]倪季良,冷却塔的落水噪声及防治措施的探讨.电力建设,2003年3月第24卷第3期,15-18.
[7]范亚菊,汤征等,火电厂冷却塔噪声治理的计算机模拟,151-152.
[8]倪季良,自然通风冷却塔的噪声污染。工业用水与废水,2001年第5期,4-6。
[9]陈新龙,城市火电厂冷却塔噪声治理.四川电力技术第5期,51-53.
[10]倪季良,冷却塔的落水噪声及其防治措施。工业用水与废水,2003年6月,55-58。
[11]吕玉恒等,特大型双曲线自然通风冷却塔噪声治理.科技纵横,22-24。
[12]毛献忠,陈允文等,逆流式自然通风冷却塔流场及热质交换的数值模拟.计算物理,1994年12月第11卷第2期,384-392.
[13]陈金思,冷却塔减噪综述。安徽化工,2002年第3期,42-43.
[14]胡华,姜学忠,大型双曲线白然通风冷却塔的噪声治理.华东电力,2003年第9期,33-36.
[15]孙建青,徐贤金,谈华,瞿浩,冷却塔噪声及其控制。水利电力劳动保护,1997年6月第2期,21-22。
[16]陈金兴,冷却塔噪声源识别及降噪途径分析.噪声污染与防治,1998年8月,31-32.
[17]赵顺安,廖内平,徐铭,逆流式自然通风冷却塔二维数值模拟优化设计.水利学报,2003年10月,26-31。
[18]徐德林,大型冷却塔噪声综合控制技术.环境工程,2002.12,43-44。
[19]淡洁,冷却塔水滴噪声及其漂浮式降噪装置.水利规划与设计,2006年第4期,55-57.
[20]Krittika Lertsawat,Supichai Tangjaitrong,Prathan Areebhol,Prediction of noise emission from power plantby a mathematical model。 Applied Acoustics 58(1999)469-477.
[21]Kragh J,Anderson B,Jakobsen J.Environmental Noise from Industrial Plants.General Prediction Method.Denmark:Danish Acoustical Laboratory,1982.
[22]G.Bisio~*,G.Rubatto,R.Martini,Heat transfer,energy saving and pollution control in UHP electric-arc furnaces o Energy 25(2000)1047-1066.
[23]Stockmeyer R et al.Einsparung von elektrischer Energie am Lichtbogenofen durch eine neue Ausqualmregelung Stahl a Eisen 1990;110:113-6.
[24]A.M.Kunesch,Water noise in large cooling tower installation。 Noise control vibration isolation,134-137.
[25]Bisio G,Benvenuto G.Possible utilizations of the pressure exergy of natural gas.1n:Proceedings of 28th IECEC,Aug 8-13;Atlanta,GE,vol.2.Washington,DC:American chemical Society,1993:167-73.
[26]Becket L,Hammer,EE.Sidewall and roof panels of a 70 t electric arc furnace with evaporative cooling system.World Steel and Metalworking 1986/87;8:26-32.
[27]Le Louer P,Engler G.Noise control in new electric steelworks,1n:Proceedings of INTER-NOISE 88,30 Aug-1 Sep;Avignon,vol.2,1988:883.
[28]Morris DR,Szargut J.Standard chemical exergy of some elements and compounds on the planet Earth.Energy,1986;11:733-55.
[29]John S.Wang,Prediction and Control of Induced Draft Cooling Tower Noise。Noise control engineering,March-April 1979,74-81.
[30]Walter L.Reinicke,Enno P.Riede,Noise from natural draft cooling tower。Noise control engineering,July-August 1980,28-36.
[31]赵振国,李志悌,石金铃,陈仙松.逆流式自然通风冷却塔通风阻力的研究[J].水动力学研究与进展,1993(4).
[32]王凯,自然通风冷却塔进风口空气动力场的数值模拟与阻力研究[D].山东大学硕士学位论文,2006.
[33]陈东民,自然通风冷却塔内流场与传质传热的数值分析,清华大学硕士学位论文,1994。
[34]朱宪然,电站自然通风湿式冷却塔空气动力场数值模拟,山东大学硕士论文,2002.
[35]王立秋,魏焕彩,周学圣.工程数值分析[M]。济南:山东大学出版社,2002。
[36]孔珑,工程流体力学.北京:中国电力出版社,1998.
[37]吴江航,韩庆书,计算流体力学的理论、方法及应用.北京:科学出版社,1988.
[38]Patankar,S.V.传热和流体流动的数值计算.安徽:安徽科学工业出版社。1984.
[39]赵元宾,基于κ-ξ紊流模型的自然通风湿式冷却塔空气动力场数值模拟.山东大学硕士论文,2005.
[40]李秀云,林万超,冷却塔的节能潜力分析,中国电力,No.10,1997.
[41]债志强,朱克勤,符松,横向风对自然通风干式冷却塔空气流场影响的模型实验研究实验力学,1997.
[42]胡三季,陈玉玲,工业冷却塔与模拟试验塔试验系数的相关关系.
[43]赵顺安,廖内平,徐铭,逆流式自然通风冷却塔二维数值模拟优化设计.
[44]赵振国,石金铃,周常虹,腾新军.冷却塔雨区的热力特性[J].水利学报,2000年第3期。
[45]薛茂,王晓宁,赵晓丹,微穿孔板吸声结构计算及其应用。江苏大学学报,2002年9月。
[46]朱羽中,冷却塔冷却效率评价计算方法.工业用水与废水,2003年12月,61-63。