Numerical simulation of capture process of fine particles in electrostatic precipitators under consideration of electrohydrodynamics flow

摘要

In the present work, a numerical method was adopted to study the capture process of fine particles in two electrostatic precipitators (ESPs) with corrugated and parallel plates, respectively.(1) The simplified models were established to evaluate and predict the distribution of electrostatic field, gas dynamic, particle charging, and transport behavior. The electrohydrodynamic (EHD) flow with different applied voltage at various gas velocities was presented on the basis of two kinds of models, and the detailed influence on particle dynamic, including particle trajectory, migration velocity to collection plates, and particle capture had also been investigated thoroughly.(2) Numerical results indicated that corrugated plate electrostatic precipitator (CP ESP),(3) possessed greater electrostatic field characteristic than parallel plate electrostatic precipitator (PP ESP) and it also had a stronger capacity of resisting the influence of EHD flow, which was beneficial from the particular structure.(4) Besides, the EHD flow would make smaller particle present more apparent fluctuant trajectory near discharge wires when fine particles traveled in ESPs at a low gas velocity or with a high applied voltage, and that caused a more severe movement towards collection plates. Numerical results of the evolution of EHD flow showed that the faster elimination of ionic wind vortexes in CP ESP gave rise to higher collection efficiency. With the increment of gas velocity, the intensity of EHD flow exhibited a declining trend, and the difference of collection efficiency between two ESPs also decreased, which suggested that EHD flow had a significant effect on the <1 mu m particle collection and the structure optimization could provide an available approach to evade the influence of EHD flow. (C) 2019 Elsevier B.V. All rights reserved.