混凝机理物理模型中混合剪切阶段的研究

在总结絮凝剪切理论和实验研究的基础上,从亚微观的角度上,提出了混凝过程的物理模型,该模型从理论上强调了絮凝剪切碰撞的有效性和结合了分形维数评价混凝效果及过程。该模型指出:只有胶体颗粒与充分分散的药剂充分接触,才有可能充分地形成微絮体,也才有可能充分地或高效地(短时间内)形成大絮体。也就是说充分地混合剪切,才有高质量的凝聚,才可能有高效地絮凝。我们强调这种混合剪切是指在一定的流体力作用下颗粒与药剂的充分分散和接触。无机絮凝剂从添加到分散,到与颗粒发生接触作用,到脱稳颗粒形成微絮体乃至以后的大絮体,它在一定的弱搅拌强度下需要一定的时间;添加有机絮凝剂时则需要较强的搅拌强度。试验也证明:在上述条件下,其混凝沉降效果大大优于传统的混凝沉降效果。

Study on Mixing Shearing Process in Coagu-flocculation Physical Model

Based on flocculation shearing theory and a large number of experiment studies, coagu-flocculation physical model was proposed in the views of sub-microcosmic, with emphasis on the effectiveness of flocculating shear collision and combination of fractal dimensions to judge effect and process of coagu-flocculation. The model shows that high quality of coagulation and high efficient flocculation occur only when mixing shearing is well developed. The mixing shearing is the very process of complete contact between particles and reagents under certain action of hydrodynamic. Inorganic flocculants, from adding, dispersing, contacting with particles to form micro-floccule even the big one, needs certain time in weak stirring intensity while the organic flocculants needs the stronger. Experiments proved that its coagu-flocculation sedimentation effect is far superior to that of the tradition.