Lagrangian simulation of turbulent particle dispersion in electrostatic precipitators

Industrial design of electrostatic precipitators Is based on the transport theory developed by Deutsch (1922), which assumes that transverse turbulent mixing is effective enough to maintain the concentration profile uniform throughout the cross section (i.e., turbulent diffusivity is assumed infinite). To improve understanding of turbulent particle dispersion under the influence of electrostatic forces, a database on particle trajectories was first generated, based on the flow field from a direct numerical simulation of a plate-plate precipitator (Soldati et al, 1993). The effect of various parameters, such as particle size, charge and particle migration velocity, on dispersion and collection efficiency was investigated. Results show that particle concentration profiles are not uniform due to finite values of ''turbulent diffusion'' coefficient. The simulations indicate that the early stages of particle collection are controlled by particle migration velocity, while final stages are controlled by turbulence diffusion mechanisms.