混合传质限速步骤及评价指标混合因子

Analysis of mass transfer in mixing process and introduction of a new evaluation factor named mixing factor

为提高水处理混合工艺的效能,须对混合传质进行有效控制及效果评价.通过动力学和数学分析,研究湍流条件下的物质扩散规律,提出亚微观扩散是传质的限速步骤,增加混凝剂投加均匀度可有效缩短混合时间(t),以n表示投药点数时,缩减系数为π2/(π+n)2;基于传统评价方法中存在的混合效率与能耗脱节的不足,提出并定义"混合因子(IH)"这一新参数,以度量单位能耗对混合剂扩散均匀程度的贡献度.作为一项反映混合效率与能耗的综合指标,IH可对不同混合装置的效能进行更为合理的评价与比较.

In order to increase the mixing efficiency in water and wastewater treatment process and evaluate the process in reason, the mass diffusion was investigated according to the dynamic and mathematic analysis. The results indicate that the submicroscopic diffusion is the limitation for mass transformation, and the mixing time （ t ） can be remarkably decreased by increasing the extender equipollence in water or wastewater. The reducing coefficient of mixing time can be expressed as π（ π ＋ n ）^2 with n as the inpouring port number. The suggested mixing factor （ I H） can synthesize mixing efficiency with energy consumption and is supposed to evaluate the efficiency of different mixing processes adequately according to the same standard.