Particle transport phenomena have significant in numerous industrial process. Recently, the research on the particle transport in a complex geometry with an electric field has been carried out in the field of air pollution control devices. It is of interest how inertial particles interact with the electric field in a complex geometry. In this study, the particle transport by electrostatic force and inertial force have been investigated in rectangular impactor with positive corona discharge. To do this work, visualization experiments and numerical simulations were performed to investigate the electrohydrodynamic flow in a rectangular slit impactor. Also image processing of deposited particles on the impaction plate and calculations of particle trajectory were performed to investigate characteristics of particle deposition in EHD flow. Smoke was used to trace the flow while flow visualization was carried out using a pulse laser sheet technique. This study focuses on the interactions between the impactor air flow (i.e., primary flow) and the electric wind due to the positive polarity of the corona discharge. In the visualization experiments, the Reynolds number for the primary flow varies from 500 to 2500 and the applied voltage on the corona discharge wire ranges from 10 kV to 12 kV. Flow visualization shows that the positive corona discharge produces a stable electrohydrodynamic flow, and that the streamlines between the throat exit and the impaction plate become narrow with decreasing electric Froude number, $F_R$. The electric field was obtained by solving the Poisson equation, and the electrohydronynamic flow patterns obtained by solving the vorticity-stream function equation with laminar flow assumption. The results of visualization experiments and numerical simulations exhibit good qualitative agreement. The trajectory model was adopted to description of the particle motion, and the equation of particle motion included inertial, viscous drag and electrostatic force. From the results of experiments for characteristics of particle deposition in EHD flow, the distribution of particle deposited on the impaction plate was more narrow for lower Re or for larger particle diameter. When the particle diameter increases or Reynolds number decreases, the peak position of normalized number of deposited particles is moved from the centerline of impaction plate.
