流场中W/O乳状液分散水滴的聚并特性

Water Droplets Coalescence Characteristics of W/O Emulsion in the Flow Fluid

为更好地认识流场中W/O乳状液分散水滴的聚并规律,利用涡轮式搅拌槽结合显微摄像技术,对水滴中位粒径变化与相关准则数的关系进行了深入研究,提出了表征惯性力与湍流场力关系的新准则数T数,并探讨了其与分散相水滴聚并特征的关系。结果表明:当含水率为20%,Re=2500~3000时,水滴中位粒径变化显著;各含水率下,对聚并最为有利的We=750~1050;随T变化,水滴中位粒径变化可分为3个区域。通过对准则数T的研究发现合理控制W/O乳状液的含水率、物性条件及流场参数可以有效克服外界条件的不利影响,促进油中水滴的聚并。

In this paper,stirred tank experiment system combined with image process software is utilized to study the Water Droplets coalescence characteristics of W/O Emulsion in flow field.The relationship between the diniensionless criterion numbers and the diameter variation is discussed in detail.The new diniensionless criterion number T is proposed to characterize the relationship between turbulent force and inertial force,and experiment is carried out to study the effect of T on the behavior of coalescence of micron-sized drops in oil.It is indicated that the diameters of droplets increased obviously when the water content is about 20% and the Renault number ranges from 2500 to 3000.In this study,the optimal range of Weber number is from 750 to 1050.The variation of the droplets can be divided into three regions with the diniensionless criterion number T.Results of the experiment on criterion number T prove that properly control of the water cut,physical properties and flowing parameters can overcome the adverse external conditions and thus effectively enhance droplets coalescence of W/O Emulsion.