Study on droplet deformation characteristics under coupled electric and magnetic fields

Electric dehydration is an efficient method for breaking stable water-in-oil emulsions, with higher recorded dehydration rates under coupled electric and magnetic fields when compared to a single electric field. However, the underlying mechanisms for droplet deformation and movement under coupling fields are still unclear. Herein, the deformation characteristics of single droplets under coupled high-voltage electric and magnetic fields were experimentally investigated through a high-speed camera system. The results indicated deformation degrees of droplets directly proportional to the electric field intensity, while droplet size showed little impact on droplet deformation. The degree of droplet deformation is affected by the magnetic field. Compared to under a single electric field, the deformation of droplets decreases under the coupled fields. Comparison of droplets' movements under coupled electric and magnetic fields revealed 3.4-fold higher horizontal movement of droplets under an alternating current (AC)-electro-magnetic coupling field than under a single AC field. The polarized electromagnetic force was obtained by analyzing the forces applied on the droplet under coupled fields. The water content of the oil after dehydration under coupled fields was less than 1 % compared to 4.7 % under a single electric field, confirming the advantages of coupled fields. Overall, these data look potential for improving crude oil dehydration efficiency and reducing energy consumption.