雨洪水回灌中多分散颗粒运移-沉积特征及数值模拟  

Physical Experiment and Modeling of the Transport and Deposition of Polydisperse Particles in Stormwater Recharge

作　　者：邹志科 李亚龙[1] 余蕾[1] 李伟[1] 罗文兵[1] 孙建东 ZOU Zhi-ke;LI Ya-long;YU Lei;LI Wei;LUO Wen-bing;SUN Jian-dong(Agricultural Water Conservancy Department, Yangtze River Scientific Research Institute, Wuhan430010, China;Sinohydro Foundation Engineering Co., Ltd., Tianjin 301700, China)

机构地区：[1]长江科学院农业水利研究所,武汉430010 [2]中国水电基础局有限公司,天津301700

出　　处：《长江科学院院报》2021年第10期126-132,共7页Journal of Changjiang River Scientific Research Institute

基　　金：国家自然科学基金委员会—中华人民共和国水利部—中国长江三峡集团有限公司长江水科学研究联合基金项目(U2040213);中央级公益性科研院所基本科研业务费项目(CKSF2021452/NY)。

摘　　要：雨洪水回灌过程中多分散颗粒造成的堵塞问题实质上是多孔介质中颗粒的运移和沉积。为了揭示饱和多孔介质中多分散颗粒的沉积特性,开展了5种不同浓度条件下多分散雨洪颗粒(0.375~55.82μm)人工回灌一维砂柱定流量试验,基于胶体过滤理论,建立多分散颗粒运移-沉积的改进模型并进行相应的数值模拟。物理试验和数值模拟结果表明:不同浓度条件下多分散颗粒的沉积剖面都符合“上陡峭,下平缓”的超指数分布,而不是常规模型预测的指数分布。超指数分布是多分散颗粒的非均等沉积造成的,常规模型均化了沉积颗粒的空间分布,Kozeny-Carman模型可以模拟颗粒的非均等沉积造成介质不同位置渗透性能降低,介质的堵塞程度与颗粒大小直接相关,介质渗透性能最大降低为原来的52%,雨洪水中粒径>2.26μm颗粒的沉积是造成堵塞的主要原因。The blockage caused by polydisperse particles in the process of stormwater recharge is in essence the transport and deposition of particles in porous media.To find deposition feature of polydisperse particles,a one-dimensional sand column test for artificial recharge is carried out to observe the outflow and inflow concentration of polydisperse particles ranging from 0.375 to 55.82μm at five injection concentrations.A modified model in consideration of the particle polydispersity is theoretically derived based on the colloid filtration theory(CFT).Both the experimental and simulation results show the retention profiles of five concentrations compile with the hyper-exponential law,rather than the exponential retention predicted by the conventional model.The highly hyper-exponential retention profiles are caused by non-uniform deposition of polydisperse particles;and,the conventional model is found to homogenize the spatial distribution of retention of polydisperse particles.Local and overall permeability reductions are assessed by the Kozeny-Carman model.The blockage degree of media is directly relevant to particle size.The permeability of the medium is reduced to 52%,and the deposition of particles larger than 2.26μm in the stormwater is the main cause of blockage.

关 键 词：雨洪水回灌 多分散颗粒 过滤系数 超指数分布 Kozeny-Carman模型 

分 类 号：TV139.16[水利工程—水力学及河流动力学]