脉冲非均匀电场下水滴运动及碰撞特性研究

Study of motion and collision characteristics of water droplets under pulsed non-uniform electric field

为了提高油包水(W/O)乳液的破乳脱水效率,采用高压方波脉冲非均匀电场,并基于显微试验研究水滴极化后的碰撞行为及微观破乳过程(水滴液膜破裂后聚结)。结果表明:非电解质促进水滴弹/塑性碰撞行为,电解质削弱偶极作用而减小碰撞速度;加入非电解质,电参数对水滴塑性碰撞的影响大于直径比和体积,而加入电解质,直径比对塑性碰撞的影响最大,其次是体积和电参数;不同电压和频率下,乳液B(含非电解质)中水滴塑性碰撞速度极大值分别为9.451μm/s和8.577μm/s,远大于乳液A(对照组)和乳液C(含电解质),其中乳液C最小。研究得到的水滴碰撞聚结规律可为提高静电聚结器的脱水效率和研制高效电脱水器提供借鉴。

In order to improve the demulsification and dehydration efficiency of water-in-oil(W/O)emulsions,a high-voltage square-wave pulsed non-uniform electric field was used,and the collision behavior of droplets after polarization and the microscopic demulsification process(agglomeration after droplet film rupture)were studied based on microscopic experiments.The results show that the non-electrolyte promotes the droplet elastic/plastic collision behavior and the electrolyte reduces the collision velocity by weakening the dipole interaction.When non-electrolytes are added,the electrical parameters have a greater effect on the plastic collision of droplets than the diameter ratio and volume,whereas when electrolytes are added,the diameter ratio has the greatest effect on the plastic collision,followed by the volume and electrical parameters.The maximum values of plastic collision velocity of droplets in emulsion B(with non-electrolyte)were 9.451μm/s and 8.577μm/s at different voltages and frequencies,which were much larger than those in emulsion A(control group)and emulsion C(containing electrolyte),and maximum value of emulsion C was the smallest.The droplets collision and coalescence rules obtained from the study can simultaneously provide a reference for improving the dehydration efficiency of electrostatic coalescers and developing high-efficiency electric dehydrators.