污水搅拌器摆放角度对流场性能影响  

Influence of wastewater mixer setting angle on flow field in sewage treatment pool

作　　者：张智 郑源[1] 蒋洁青 李城易 ZHANG Zhi;ZHENG Yuan;JIANG Jieqing;LI Chengyi(College of Energy and Electrical,Hohai University,Nanjing,Jiangsu 210098,China;East China Yixing Pumped Storage Power Co.Ltd.,Yixing,Jiangsu 214205,China)

机构地区：[1]河海大学能源与电气学院,江苏南京210098 [2]华东宜兴抽水蓄能有限公司,江苏宜兴214205

出　　处：《排灌机械工程学报》2020年第3期271-276,共6页Journal of Drainage and Irrigation Machinery Engineering

基　　金：国家自然科学基金重点资助项目(51339005);国家自然科学基金面上资助项目(51579080)。

摘　　要：针对搅拌器摆放角度不合理、污水处理池内液体能耗过大造成的底部流速较低等问题,基于Fluent对搅拌器在不同摆放角度下的流场进行数值模拟,以优化设计、减少污泥沉淀.通过UG建立三维实体模型并进行四面体网格划分,利用标准k-ε湍流模型以及SIMPLEC算法对处理池进行模拟.在改变搅拌器摆放角度的情况下,对比处理池内的流速分布情况和平均速度大小,得出不同摆放角度对搅拌器推流搅拌效果的影响;同时还对流场中旋涡结构与搅拌能耗的关系进行了研究.结果表明:摆放角度为50°时,底部截面平均流速最大提高17.6%,体平均流速可提高6%,最大降低底部死区率12%,推流搅拌效果最佳.同时,搅拌效果也受旋涡结构影响,旋涡数量越少,单个旋涡尺度越大,旋涡能耗越低,流态越平稳,推流搅拌效果越好.可以通过改变搅拌器摆放角度,改善内部流态,减少污泥沉淀现象,降低旋涡能耗,达到改善推流搅拌效果的目的.An unreasonable setting angle can result in a wastewater mixer to consume much more po-wer.Bearing this problem in mind,three-dimensional turbulent fluid flows in a sewage water treatment pool with two wastewater mixers at various setting angles were simulated using Fluent software to optimize mixer design and reduce sludge deposition at the pool bottom due to low water velocity.At first,the three-dimensional fluid domain model was established in UG software,then the steady fluid flow field was calculated in unstructured tetrahedron grids based on the N-S equations,standard k-εturbulent flow model and SIMPLEC algorithm.The average velocity and velocity distribution within the pool were compared among various setting angles.Consequently,flow mixing effect was assessed by employing grayscale correlation method in terms of low velocity zone occurrence rate at the pool bottom.At the same time,the relationship between vortex structure and mixing energy consumption was studied.The results show that when the angle is 50°,the average fluid velocity at the bottom is increased by 17.6%,the volume-averaged velocity is increased by 6%,and the low velocity zone occurrence rate at the bottom is reduced by 12%,suggesting the best transporting and mixing effect.Additionally,the vortex phenomenon has a significant impact on stirring effect.The smaller the number of vortices and the larger the scale of a single vortex,the lower the energy consumption and the more stable.the fluid flow,the better the mixing effect.Altering the setting angle of a wastewater mixer can improve fluid flow pattern in a sewage water treatment pool,suppress sludge deposition and reduce energy consumption of vortex,eventually to achieve an aim with advanced transporting and mixing effect.

关 键 词：污水处理搅拌器 数值模拟 摆放角度 旋涡 灰度关联法 

分 类 号：S277.9[农业科学—农业水土工程]