Experimental Investigation of the Electric Field and the Electrohydrodynamic(EHD) Flow in Electrostatic Separator

The electric field and electrohydrodynamic(EHD) flow field of a small scale wire-plate electrostatic separator,which is used for the separation oil droplets with an average diameter of 2 μm from air flow,is experimentally studied under positive polarity.The current-voltage characteristics(CVC) curves are tested under different primary gas flows and different oil droplets concentrations.The EHD flow field is visualized under different operating conditions by high speed camera.The tested gas velocities are 0.2 m/s,0.3 m/s and 0.4 m/s respectively,and the applied voltage is from 0～16 kV.The EHD flow map is obtained under different gas velocities and applied voltage.Experimental results show that the influence of gas velocity on the electric field is negligible.However,the oil droplets concentration has great impacts on the electric field.The current density decreased with the increase of oil concentration.The EHD flow patterns change significantly during corona discharge,depending on the gas velocity and applied voltage.Five typical EHD flow patterns are captured under different Reynolds number and EHD number,which represents the relationship between inertial forces and electrical forces.