供水管道漏损流化区域数值仿真模拟

Simulation of Soil Fluidization Due to the Leakage on Water Supply Pipe

管网漏损仍然是中国城市供水系统面临的一个重大问题。供水管网漏损后,会发生出射的高速水流令土体颗粒流化自由移动,水流裹挟土颗粒冲蚀外管壁,进一步造成管壁变薄,最终引起管道破坏,造成爆管。本文采用CFD(computational fluid dynamics)模拟手段对土壤内部流化的发展过程和漏孔处的流场速度分布规律进行仿真模拟,研究结果表明流化区域呈现倒圆锥状,初期纵向发展,被水流裹挟的砂颗粒部分向上压实形成土拱,纵向发展至一定高度后,部分砂颗粒堆存于两侧,压实两侧填砂区域,从而向横向发展。该研究初步揭示了漏损引起土体流化的过程与机理,对于供水系统漏损控制,爆管防护具有重要的科学价值。

Leakage in the pipe network is a major problem in urban water supply system.After the leakage of the water supply network,the outgoing high-speed water flow will cause the soil particles to fluidize and move freely.The water will carry the soil particles to erode the outer pipe wall,which will further cause the thinning of the pipe wall and eventually cause the pipe damage and pipe burst.This study uses CFD(computational fluid dynamics)simulation method to simulate the development process of fluidization of the soil particle and the velocity distribution of the flow field at the leakage hole.The results show that the fluidization area shows an inverted cone shape.In the initial stage,the sand particles carried by the water flow are compacted upward to form a soil arch.In the following stage,the sand particles are deposited on both sides,compacting the sand-filled area on.The study reveals the process and mechanism of soil fluidization caused by leakage,which has important scientific value for water supply system control and management of leakage as well as pipe burst in water supply system.