絮体破碎过程的仿真及试验分析

为深入探讨絮体成长特征及其结构改善途径,借助一种简化的破碎模式对絮体破碎过程进行计算机仿真,并将仿真结果用于分析不同水动力学条件下破碎后再形成时絮体粒度和结构的演变过程.结果表明,与远离质心的区域内颗粒重组相比,絮体致密性主要取决于其质心附近颗粒的空间分布;絮体破碎后生成粒度较小但结构较为致密的碎片,在适宜的水动力学条件下有利于颗粒进入其内部或者均匀地排列在其周围,实现质心附近颗粒的重组,进而改善絮体结构.此外,还建立了絮体分形生长模型,并对絮凝工艺的操作提出优化建议.

Numerical and experimental analyses of floc breakage process

In order to deeply explore floc growth characteristics and structural improvement approaches, the process of floc breakage was simulated by computer based on a simplified breakage mode, and then simulation results were used to analyze the evolution of floc size and structure during reformation after breakage in different hydrodynamic conditions. The results showed that compared to restructure of particles far away from floc mass center, floc compactness is highly dependent on the spatial distribution of particles in the vicinity of its mass center; floc fragments formed after breakage, with a relatively small size and compact structure, benefit particles to enter into their interiors or be uniformly arranged arround them, bringing about restructure of particles nearby the mass center, and thus modifying floc structure. Moreover, a fractal growth model of floc was established, and according to the model, some suggestion was proposed for optimizing the operation of flocculation.