冷却塔淋水填料特性及结构优化实验研究

发布时间：2018-05-25 15:29

本文选题：淋水填料 + 热质交换　；参考：《东华大学》2014年硕士论文

【摘要】：随着人们节能环保意识的提升,如何提高冷却塔的工作效率越来越受到人们的关注。淋水填料作为开式冷却塔的核心部件,其热工及阻力性能直接影响着冷却塔的运行效率。而如今淋水填料的种类和片材结构层出不穷,但对其热工性能的测量往往都采用露天测试,气象参数并不稳定,而且测试不将填料段单独区分开来测量,测量数据和经验公式在实际工程中的选用会形成较大的误差。很多填料结构的改进优化没有实验数据的支撑,性能提高率常常是未知的。基于这样的背景,本文专门搭建逆流塔淋水填料测试平台,规范测试技术,对片距不同及结构改进前后的淋水填料,以及不同波形的填料进行热工性能测量和分析。首先本文系统地分析了逆流冷却塔淋水填料层的热质交换,参考相关文献,利用麦克尔方程和辛普逊积分法,建立了填料层内的热、质交换数学模型。随后通过Matlab编译了计算程序,通过输入原始工况参数,可以计算出淋水填料层喷淋水出口的水温,以及填料的冷却效率。此数学模型在之后通过实验进行验证,得到填料出口喷淋水计算温度与实测值的最大误差在0.75%,冷却效率模拟计算值与实测计算值最大误差在7.7%,该误差在工程允许范围内。本文对四种高度为600mm的斜交错塑料淋水填料进行性能测试,填料规格分别是传统粘接片距15mm和片距12mm斜交错填料,以及优化改进为嵌入点粘接片距为12mm和19mm斜交错填料。实验结果表明嵌入点粘接能对填料性能起到较大的优化。淋水密度在6-10m3/(m2·h),填料迎风速度在1～-2.6m/s时,嵌入点粘接片距为12mm斜交错填料阻力值是传统粘接片距12mm斜交错填料阻力的93.2%～98.14%,气水比在0.6-1.2之间,特性数依次提高约22.0%～29.2%。此外,嵌入点粘接的淋水填料,减小片距能很大程度地提高其冷却性。传统粘接小片距12mmm斜交错填料阻力比片距15mm填料大,但冷却性能提高率并不理想。嵌入点粘接片距为12mmm的填料比19mmm阻力略大,但在常用气水比范围内,其冷却数比片距19mmm填料提高了约45%～53%。本文另外对S波型,人字波型以及复合波型,高1000mm的三种工业用中高温填料进行测试。测试结果显示：S波型填料阻力最大,其次是人字波,复合波型填料通风阻力最小。淋水密度在6-10m3/(m2·h),在常用气水比范围内,复合波型填料冷却数是人字波型的1.08-1.34倍,是S波型的1.06～1.1倍。最后,本文以20t/h方形逆流塔为实际工程案例,分析选用之前实验测试的四种斜交错淋水填料,得到四种填料在该工程中合理的气水比。与此同时,计算它们在各自最合理的运行工况下填料层的空气阻力,结果显示嵌入点粘接片距12mmm填料层的阻力最小,为14.76Pa；传统粘接片距15mm填料的阻力最大,为24.93Pa。最后对整个冷却塔进行运行分析,得出选用嵌入点粘接的大片距19mmm斜交错填料的冷却塔风机电机功率最大,为1.1kw；选用嵌入点粘接的小片距12mmm斜交错淋填料的冷却塔风机电机功率最小,仅为0.37kw。
[Abstract]:With the improvement of people ' s energy - saving and environmental protection consciousness , how to improve the working efficiency of cooling tower has been paid more and more attention .

Based on this background , this paper specially sets up the test platform of counter - current tower , the specification and test technology , the water - sprinkling filling before and after the structure improvement , and the thermal performance measurement and analysis of different wave - shaped fillers .

In this paper , a mathematical model of heat and mass exchange in the packing layer is established by using the Maxwell equation and the Simpson integral method . The water temperature of the spray water outlet and the cooling efficiency of the packing are calculated by Matlab . The maximum error of the spray water at the outlet of the packing is 0.75 % , and the maximum error of the cooling efficiency is 7.7 % . The error is within the allowable range of the project .

The experimental results show that the adhesive sheet has a better cooling performance than that of the conventional adhesive sheet with a distance of 6 - 10m3 / ( m2 路 h ) , and the air - water ratio is between 0.6 and 1.2 % .

The results show that the resistance of S - wave type packing is the biggest , the second is the herringbone wave , and the ventilation resistance of the composite wave - type packing is the least . The density of the composite wave - type packing is 1 . 08 - 1 . 34 times of that of the herringbone wave , and it is 1.06 - 1.1 times of the S - wave type .

Finally , this paper takes 20t / h square counter - flow tower as the practical engineering case , and analyzes the four kinds of oblique cross - staggered water - pouring fillers which are used in the previous experiment to obtain the reasonable gas - water ratio of the four kinds of fillers in the project . At the same time , the air resistance of the packing layer under the most reasonable operating conditions is calculated , and the result shows that the resistance of the embedded - point adhesive sheet to the filler layer of 12 mm is minimum , which is 14.76Pa ;
The maximum resistance of the traditional adhesive sheet to 15mm packing is 24.93Pa . Finally , the whole cooling tower is run and analyzed , and it is concluded that the maximum power of the fan motor is 1.1 kw .
The minimum power of the fan motor of cooling tower with the small sheet spacing of 12 mm from the embedding point is only 0.37 kw .
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB657;TU831

【参考文献】