匀强电场作用下分散相液滴的变形和破裂

Deformation and breakup of dispersed phase droplets in uniform electric field

基于Cahn-Hilliard方程的相场方法,建立了在匀强电场作用下液滴的变形和破裂行为模型。从微观角度研究分散相液滴变形过程中电荷密度、电场强度和电场力的分布规律以及流场和电场分布,探讨了微观液滴变形机理;采用数值模拟方法研究了电场强度、液滴直径和界面张力对液滴变形的影响,结果表明电场强度越强,液滴直径越大,界面张力越小,液滴变形量越大;分析了液滴的两种主要破裂方式,其破裂主要取决于连续相和分散相物性条件,为电破乳技术提供了理论基础。

Through coupling hydrodynamics and electrostatics, a phase field method based on Cahn-Hilliard formulation was used to predict the deformation and breakup of dispersed phase droplets in a uniform electric field. The distribution of charge density, electric field strength and electric field force on the droplet surface as well as the distribution of flow field and electric field were studied from the micro-perspective. The micro-droplet deformation mechanism was established. The influence of electric field strength, droplet diameter and interfacial tension on the deformation was predicted by numerical simulation. The results showed that strong electric field intensity, large droplet diameter or small interracial tension could cause larger degree of droplet deformation. The droplet mainly ruptured from its middle or the two ends. Rupture mainly depended on the physical properties of the continuous phase and dispersed phase. The above study would provide a theoretical basis for complex electric demulsification.