An improved modeling for Collection Efficiency prediction of electrostatic precipitators under the applied magnetic field

This paper describes a strongly coupled calculation procedure for the particle dynamics in electrostatic precipitators (ESP) subjected to the applied magnetic field with the statistical particle size distribution taken into account. The turbulent gas flow and the particle motion under external forces are modeled by using the commercial computational fluid dynamics (CFD) code FLUENT. Numerical calculations for the gas flow are carried out by solving the Reynolds-averaged Navier-Stokes equations and turbulence is modeled using the k-epsilon turbulence model. An additional source term, which is obtained by solving a coupled system of the electromagnetic field and charge transport equations, is added to the gas flow equation to capture the effect of electromagnetic field. Discrete Phase Model (DPM) is employed to achieve the simulation of the particle phase. Different kinds of particles which follow Rosin-Rammler distribution were simulated under different conditions, and the influence of magnetic field density on the capture of fine particle was investigated. In order to show the dust removal effect, the collection efficiency and the escaped particle size distribution were discussed in case of different applied magnetic fields. The particles trajectories inside the ESP were also given under the effects of both aerodynamic and electromagnetic forces. Numerical results indicate that the collection efficiency increases with the increase of applied magnetic field, that the particles trajectory are more visible to the direction of dust collection plate, and that the collection efficiency varies smoothly when the applied magnetic field is up to a certain value. Furthermore, the average diameter of escaping particles decreases and the dispersion for dust particles in different size increases with applied magnetic field increasing, and particle sizes is linearly decreasing with magnetic field before the particle reaches a certain size.