局部淤堵排水管道水力冲击特性的CFD模拟研究

CFD simulation study on hydraulic impact characteristics of partially silted drainage pipelines

在市政排水管道中,长时间运行会导致排水管道发生局部淤堵,降低过流能力,对排水管道正常运行产生影响.本文针对存在局部淤堵的圆形截面排水管道构建了水汽两相流数值模型,利用CFD手段模拟研究了非恒定入流边界下的局部淤堵排水管道水力特性,量化分析了不同初始条件下淤积或障碍物的受力情况.结果分析表明:在干管初始条件下,冲击瞬间障碍物受力达到最大值,该冲击力可用射流公式近似计算,相对误差小于10%;而在湿管条件下,水流对于障碍物的冲击力相较干管有显著下降.此外在湿管条件下,障碍物受水流冲击的强度还与初始条件下障碍物的淹没条件密切相关.

n municipal drainage pipelines,long term operation can cause local blockage,reduce the flow capacity,and affect the normal operation of drainage pipelines.This study presents a numerical model of two-phase air-water flow for circular cross-section drainage pipes with localized clogging,the hydraulic characteristics of drainage pipes with localized clogging under non-steady inflow boundaries were simulated using CFD mothods,and the force exerted on sedimentation or obstacles under different operating conditions was quantitaively analyzed.The results analysis showed that under dry-pipe initial conditions,the maximum force on the obstacle occurs during the impact moment,and this impact force can be approximated using the jet impinging with a relative error of less than 10%.On the other hand,under wet-pipe conditions(with base flow initially),the impact force of water flow on obstacles is significantly lower than that of dry-pipe conditions.In addition,under wet-pipe conditions,the intensity of the impact of increased flow on obstacles is closely related to the initial submerged conditions.