温度对黏性泥沙絮凝影响的机理研究

用格子玻耳兹曼方法,引入胶体作用理论(e Xtended Derjaguin-Landau-Verwey-Overbeek theory,XDLVO理论)模拟不同温度下两个黏性泥沙颗粒静水不等速沉降絮凝过程。结果表明,温度升高缩短泥沙絮凝时间,促进絮凝。同时分析了泥沙颗粒的运动轨迹、相对运动速度和颗粒间近距离作用力,探讨温度对泥沙絮凝的影响机理。分析结果认为温度升高一方面减小水体黏性系数,加大泥沙沉速,加快泥沙颗粒相互靠近;另一方面,增大泥沙颗粒表面吸附水膜厚度的同时,也增大泥沙颗粒之间的近距离排斥力,对吸附水膜厚度和排斥力影响的综合结果也促进了絮凝。

Study on the influence of temperature to cohesive sediment flocculation

Flocculation processes of two cohesive sediment particles in quiescent water under different water temperatures are investigated based on the Lattice Boltzmann model and the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory.Results show that the high temperature will shorten the flocculation time and promote the flocculation processes.Furthermore,the particle trajectories,relative velocities and the inter-particle forces at short distance of the two particles are analyzed to discuss the flocculation mechanism due to the temperature.The analyzed results reveal that the higher temperature,on the one hand,decreases the water viscosity and increases the settling velocities of particles,to make particles easier to aggregate into floc.On the other hand,the temperature increases the thickness of the absorbed water film on particle surface with a repulsion force between them.Finally,the combined effect on the flocculation is helpful to flocculation.