Experiment and Analysis of Flow Field in a Wire-Duct Type Electrostatic Precipitator

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1. Analysis of corona discharging electric field : A new method of solving the equations that describe the space charge field in a wire-duct type electrostatic precipitator is presented. The theoretical values of corona current-voltage characteristics, coronacurrent density and electric field distributions on the plate are calculated by the new method and are in good agreement with the measured values. This method is used to find the distributions of potential, charge density and electric field in the gas space between the discharge and plates.2. Analysis of flow in ESP : The effects of corona discharge on the flow field are numerically analyzed on the basis of Navier-Stokes equations with external force as Coulomb force density and the continuity equation. Time-dependent vorticity is calculated by alternating direction implicit method while Poisson equation for vorticity and stream function by finite element method. As a result, the characteristics of electrohydrodynamic flow field are clearly obtained as a function of electrohydrodynamic number which is defined as a ratio of characteristic ionic wind velocity and inlet flow velocity.3. Experiment of flow field in ESP : The flow field in ESP is visualized and photographed by Schilieren method. As a result, the effects of both on the flow field in ESP and of vortex near collecting plate electrode are clearly observed in the experiment. It is found that the similarity law concerning to flow field in ESP holds : the patterns of flow field are nearly similar for the same electrohydrodhnamic number.