城市污水交汇管流模型构建与管道污染物运动特性研究  

Intersection model construction of urban sewage pipe and study on the movement characteristics of pollutants

作　　者：刘丹[1] 石烜[1] 薛甜 赵楠[1] 任博 金鹏康[1] Liu Dan;Shi Xuan;Xue Tian;Zhao Nan;Ren Bo;Jin Pengkang(School of Environmental and Municipal Engineering,Xi’an University of Architecture and Technology,Xi’an 710055,China)

机构地区：[1]西安建筑科技大学环境与市政工程学院,西安710055

出　　处：《给水排水》2020年第4期144-149,153,共7页Water & Wastewater Engineering

摘　　要：针对城市污水管网交汇导致污染物沉积加重的问题,通过中试和Fluent三维数值模拟VOF耦合DPM模型相结合的方法,研究了污水管网交汇流态变化及其对碳、氮、磷3类污染物运动特性的影响规律。结果表明,污水管网交汇段形成了不同的流态分区,依据水流特征可将其分为水流停滞区、大流速区、流速偏折区、回流分离区、最大流速区和流动复原区。纵深方向上,水流停滞区和回流分离区范围由表层至底层逐渐减小直至消失;沿程方向上,交汇前速度分布比交汇后受支流入汇影响较小,交汇下游整体流速比交汇上游大。受不同交汇流态分区的影响,污水中悬浮颗粒物运动轨迹不同,颗粒物在回流分离区沉降显著,该区域TCOD、TN、TP的浓度最高,水流停滞区次之,在交汇下游流动复原区内,颗粒物逐渐趋于稳定不再继续沉降,污染物浓度随之降低。TCOD、TN、TP沿程浓度最大变化率分别为61.2%、32.7%和24.2%,在低流速下碳类污染物较氮、磷类污染物更易发生沉降。Aiming at the problem of pollutants deposition aggravated by the intersection of urban sewage pipe network,through the pilot test and Fluent 3 Dnumerical simulation of VOF coupled DPM model,studying the variation of intersection flow for sewage pipe network and its influence on the movement characteristics of carbon,nitrogen and phosphorus pollutants.The results show that the different flow zones were formed in the intersection of sewage network,which could be divided into stagnation zone,large velocity zone,deviation zone,reflux separation zone,maximum velocity zone and recovery zone according to the flow characteristics.In the direction of depth,the range of stagnation zone and reflux separation zone decreased gradually from the surface layer to the bottom layer until they disappeared.Along the direction of flow,the velocity distribution before intersection was less affected by branch inflow than after intersection,and the overall velocity at the downstream of the intersection was larger than the upstream of the intersection.Influenced by different intersection partition,the suspending particles trajectories in sewage was different.The particle deposition was the significant in the reflux separation zone and the concentration of TCOD,TN and TP in the reflux separation zone was the highest,followed by the stagnation zone.In the recovery zone at the downstream of intersection,the particles gradually became stable and stopped settling,and the pollutants concentration decreased accordingly.The maximum change rates of TCOD,TN and TP concentration along the course were 61.2%,32.7%and 24.2%,and carbon pollutants were more likely to settle than nitrogen and phosphorus pollutants at low flow rates.

关 键 词：污水管网 管流交汇 管道流态 污染物运动特性 数值模拟 

分 类 号：TU992[建筑科学—市政工程]