The movement of charged Particles in an electrical field is of practical importance in filtration efficiency and in electrostatic coating. In this paper, both of these applications have been investigated computationally. For the case of filtration, a mathematical model is introduced for the electric filter, which is made of split type fibers. The filter was assumed to be composed of rectangular fibers arranged in a staggered array field. Simulation was conducted to study filtration efficiency. Single fiber efficiencies under various filtration conditions were calculated and compared with results obtained from semiempirical expressions. In the electrostatic powder painting, gas flow and Particle flow fields inside a coating booth under given operating conditions are considered and the effects of Particle size on their trajectories are studied. Steady state turbulent gas flow is simulated by solving incompressible Navier-Stokes equations and the standard k-e" turbulence model. The discrete phase of Particles is modeled based on the Lagrangian approach. In both cases studied here, the flow field and the collection mechanisms were accurately simulated experimental observations.