电场作用下W/O乳化液中水颗粒的形变模拟与动力学分析

Deformation Simulation and Kinetics Analysis of Water Droplet in W/O Emulsions Under Electric Field

采用COMSOL MultipysicsTM软件,对W/O乳化液中分散相水颗粒在电场作用下的变形特性进行数值模拟,并结合已开展的室内实验,讨论电场强度(E)、电压波形、电场频率(f)、水颗粒半径(r)和连续相黏度(μc)对单个水颗粒变形的影响。结果表明:增加电场强度、增大水颗粒半径、降低连续相黏度会加剧水颗粒变形,电场强度存在上临界值;当电场频率较低时其值变化对水颗粒变形影响不明显,频率较高时则影响显著,但总体来看存在一个最优电场频率(2000 Hz);交流矩形波对水颗粒变形的影响强于交流锯齿波、直流脉冲波、交流三角波、交流正弦波等波形。当E为3~4 kV/cm、r为0.25~0.5 mm、使用交流矩形波时,水颗粒的拉伸发生增速变形,从而缩短水滴间的碰撞时间和W/O乳化液的电场破乳时间。

COMSOL multipysicsTM was used to simulate the deformation characteristics of water droplet in W/O emulsion under the action of electric field.The effects of electric field intensity(E),voltage waveform,electric field frequency(f),radius of water droplet(r)and viscosity of continuous phase(μc)on the deformation of single water droplet were discussed.The results show that increasing the electric field intensity,increasing the radius of water droplet and reducing the viscosity of continuous phase will promote the deformation of water droplet,and there is an upper critical value of electric field intensity;the frequency change of low frequency electric field has no significant effect on the deformation of water droplet,while the influence of high frequency is obvious,and there is an optimal electric field frequency(2000 Hz).The influence of AC rectangular wave on water droplet deformation is stronger than AC sawtooth wave,DC pulse wave,AC triangle wave and AC sine wave.When the electric field intensity is 3-4 kV/cm,the radius of water droplet is 0.25-0.5 mm,and AC rectangular wave is used,the tensile deformation of water droplet can be accelerated,so as to shorten the collision time between water droplets and the demulsification time of W/O emulsion in electric field.