Characteristics of electrical dispersion from water film flowing down an inclined plate into a dielectric liquid phase - Drop diameter, drop velocity and dispersed-phase holdup.

Abstract

An experimental study was carried out for the dispersion of water drops from a water film which flowed down an inclined plate with notched flash-boards into a continuous dielectric liquid phase in an electric field. Hydrodynamic characteristics of the dispersion were examined experimentally for three kinds of continuous phase. An empirical equation is proposed for the Sauter mean diameter of drops dispersed in the electric field. It is confirmed that the moving velocities of drops can be closely estimated by an empirical equation of Takamatsu et al. Dispersed-phase holdup is correlated with dimensionless electric stress, which is determined by physical properties of the liquids used and operating conditions. An empirical equation including the effect of the distance between two flash-boards, L, on the holdup is proposed in the range of 30 < L < 50 mm. The effect of distance is explained quantitatively by electric field strength on water film on the flash-board, calculated numerically by the boundary element method.