基于絮凝动力学的泥沙絮凝沉降规律研究

Study on sediment flocculation and settlement law based on flocculation kinetics

泥沙絮凝是一个极为复杂的过程,与泥沙浓度、颗粒表面化学性质和水环境密切相关。而现有的泥沙絮凝沉降动力学模式多采用一级模式,其絮凝速率系数往往通过实验数据拟合得到,缺乏一定的理论基础。基于DLVO理论的絮凝发生条件及胶体理论中的絮凝动力学原理,推导出静水条件下泥沙絮凝动力学方程和絮凝速率系数,由此得到絮凝过程的半衰期及絮凝平均沉降速度等参数。实验数据验证表明:推导的絮凝动力学方程计算结果与实验数据较为吻会,且影响因素考虑较为全面,推导出的絮凝速率系数表达式中将扩散系数、泥沙含沙量、离子浓度、分形维数和颗粒粒径等相关物理参数关联起来,更能体现絮凝的实质。

Sediment flocculation is an extremely complex process,which is closely related to sediment concentration,particle surface chemistry and water environment.Among the existing sediment flocculation and settlement dynamics models,the first-level model is widely used for research,and the flocculation rate coefficients are often obtained by fitting experimental data,with strong experience and simple mechanism analysis.In this paper,based on the flocculation conditions of DLVO theory and the flocculation kinetics principle of colloid theory,the flocculation kinetics equation and flocculation rate coefficient of sediment under static conditions were derived,the half-life and average settling velocity of the flocculation process were obtained.The experimental data showed that the calculated results of the flocculation kinetic equation were in good agreement with the experimental data,and the influencing factors were comprehensive.The expression of flocculation rate coefficient was related to the physical parameters such as diffusion coefficient,sediment concentration,ion concentration,fractal dimension and particle size,which can better reflect the essence of flocculation.