Abstract:

At the present time, there is no good means for calculating electrostatic force between two ellipsoidal drops in the process of electro-demulsification.In this paper, a “two-molecule” model of ellipsoidal drop was established.And then the ellipsoid situation was transformed into sphere situation by coordinate transformation.By utilizing bipolar coordinates and Maxwell stress tensor, the expression of electrostatic radial and tangential forces between two drops was deduced.The numerical calculation results showed that when the space between drops was large, electrostatic forces calculated by the model agreed well with those by the dipole model, and critical angle of attraction- repulsion, after being modified, was in good agreement with Eow’s test result.When the space between drops was small, the model was applicable to calculating electrostatic forces and critical angle between drops，and the calculating numerical values were larger than those obtained on condition that the space between drops was large, it could indicate clearly that the space between drops had a great influence on distribution of polarization charges on drops surface.