紊动和温度联合作用对黏性泥沙絮凝沉降影响试验研究  

Experimental study on the effect of turbulence and temperature on the flocculation and settling of cohesive sediments

作　　者：梁家雄 张金凤[1,2] 周惟於 陈嘉禹 LIANG Jia-xiong;ZHANG Jin-feng;ZHOU Wei-yu;CHEN Jia-yu(Key State Key Laboratory of Hydraulic Engineering Simulation and Safety,Tianjin University,Tianjin 300350,China;Key laboratory of Earthquake Engineering Simulation and Seismic Resilience,China Earthquake Administration(Tianjin University),Tianjin 300350,China;Department of Mechanics and Engineering Science,College of Engineering,Peking University,Beijing 100871,China)

机构地区：[1]天津大学水利工程仿真与安全国家重点实验室,天津300350 [2]中国地震局地震工程综合模拟与城乡抗震韧性重点实验室(天津大学),天津300350 [3]北京大学工学院力学与工程科学系,北京100871

出　　处：《泥沙研究》2021年第5期9-14,共6页Journal of Sediment Research

基　　金：国家自然科学基金联合基金重点项目(U1906231);国家自然科学基金项目(51579171);广东省水利科技创新项目(2017-17)。

摘　　要：河口海岸地区,黏性泥沙絮凝沉降特性对泥沙输移起着重要作用。影响黏性泥沙絮凝的因素很多,其中水体剪切和温度是两个重要因素。利用一种温度和紊流同时可控的泥沙沉降观测实验装置,以高岭土为实验材料,研究了紊动和温度联合作用下对黏性泥沙絮凝沉降的影响规律。研究发现弱紊动条件下,随着温度的升高,高岭土浓度变化越快;强紊动条件下,温度对浓度变化的影响不明显。絮团粒径随温度升高而增大,随着紊动强度的增加先增大后减小。相同剪切率条件下,絮团沉降速度随温度的升高而增加;相同温度条件下,絮团沉降速度随紊动强度的增加先增大后减小,主要是由于小剪切强度条件会促进絮凝,而剪切率增大能抑制絮凝,导致大絮团破裂形成小絮团。Flocculation and sediment deposition characteristics of cohesive sediment play an important role for sediment transport in estuary and coast.Factors influence cohesive sediment flocculation include turbulence and temperature.Influences of turbulence and temperature on the flocculation and kaolinite sediment of are studied by a temperature-turbulence-controlled settling cylinder.It is found that under weak turbulence conditions,the concentration of kaolin changes faster as the temperature increases;while under strong turbulence conditions,the effect of temperature on concentration change is not obvious.Floc size increases with the increase of temperature,while as turbulence intensity increases,the floc size increases first and then decreases.Similarly,settling velocity increases with the increase of temperature,but tends to increase slightly and then decrease with the increase of turbulence intensity.The mechanism is that the condition of small shear rate promotes flocculation,while the increase of shear rate inhibits flocculation,inducing large flocs to break up and form small flocs.

关 键 词：黏性泥沙 高岭土 絮凝 沉降筒 紊动 温度 

分 类 号：TV142.1[水利工程—水力学及河流动力学]