Numerical simulation of droplet deformation in low frequency half-sinusoidal electric field

Abstract

For investigating the influence of various parameters on the droplet deformation under the AC electric field condition, a simulation model for the droplet deformation in immiscible two fluids was established based on the phase field method. The distribution of flow field and electric field force are analyzed by simulation; the effects of electric field frequency, electric field intensity, droplet diameter, surface tension and continuous phase viscosity on the droplet deformation are simulated under the half-sinusoidal wave electric field condition. The simulation is performed in the low frequency half-sinusoidal waveform electric field. The simulation results show that the frequency of droplet oscillation is the same as that of the electric field. With the increase of electric field intensity and droplet diameter, the droplet deformation increases. However, the increase presents exponentially and linearly, respectively. Besides, the droplet deformation decreases exponentially with the surface tension increasing, and linearly with the continuous phase viscosity increasing. Under the condition of small deformation, there exists a linear relationship between the droplet maximum deformation and the Weber Number. More important, the influence of various factors on the deformation from strong to weak is electric field intensity, droplet diameter, surface tension, electric field frequency, continuous phase viscosity. And there is interaction between these factors. The simulation results provide theory evidence for the further research on electrostatic coalescence mechanism and the development of effective and compact electrostatic coalescence equipment.

Graphical abstract

Keywords:

• Low-frequency half-sinusoidal electric field
• W/O emulsion
• two-phase flow
• deformation variation
• numerical simulation

Additional information

Funding

This work was supported by National Natural Science Foundation of China [grant number 21406267], the Fundamental Research Funds for the Central Universities [grant number 18CX02122A], and the State Key Laboratory of Heavy Oil Processing [grant number SLKZZ-2017013].