| The electrode configuration in the electrostatic precipitator affects its electrical characteristics and the movement of the fluid,which in turn affects the capture of fine particulate matters.This paper aims to investigate the effect of the form of electrode configuration within an orifice plate precipitator o the ionic wind and dust removal efficiency by using COMSOL Multiphysics numerical simulation software and a dry experimental system and particle image velocimetry.The orifice plate composite membrane electrode is proposed in a wet system to improve the capture efficiency of fine particulate matters.The main studies are as follows.Firstly,a multi-physics field coupling numerical analysis of the electrostatic and turbulent fields and the particle charge field in the electrostatic precipitator under the electrode configuration form with a round rod-aperture plate is carried out to provide a theoretical basis for the experiments.In comparison with the flat plate electrodes,it is found that the aperture plate electrodes have following advantages: there is a rapid increase in the electric field intensity at the opening of the plate,the charge density at the aperture plate is less than that of the flat plate,which reduces the back corona phenomenon,the resistance formed by the openings weaks the ion wind vortex at the plate,the charge quantity of the aperture plate is two to four times higher than that of the flat plate for the same particle size.Secondly,an experimental model same as the numerical simulation model is built up.(1)The V-I characteristics and dust removal efficiency of the needle electrode with orifice plate are investigated in the dry experimental system.The optimal parameters of the dry orifice plate dust collector are primarily obtained.The dust removal efficiency is higher and the electrical performance is more stable with a bilateral arrangement and an opening rate of 30% and a hole arrangement of 411-type.Then,the optimal parameters of the orifice plate dust collector are investigated in terms of the different tip radii of curvature and the length and angle of the tip of the needle electrode and its optimal matching method.The dust removal efficiency in a wider voltage range can be improved under the 0.5 mm tip radius of curvature with the orifice plate.The dust removal efficiency of large particle size at a lower voltage can be improved under the 0.5 mm tip radius of curvature with the flat plate.Under the 20.0 mm needle length and the moderate orifice plate,the charge on the plate surface is uniform which is more conducive for dust collection.The needle tip at 90°with the orifice plate is more suitable for the treatment of fine dust escaping near the outlet,the needle tip at 45° can stabilize the pressure rise,which is suitable for the treatment of high dust concentration near the entrance.(2)In the wet system,it is found that the composite membrane electrode of the orifice plate can effectively prevent splashing,has strong water-saving and water distribution,and the corona current value is smaller than that of the metal plate,and the electric field strength can be steadily increased,which is conducive to the capture of microfine dust.Thirdly,a particle image velocimetry system is built to analyze the flow field changes at different tip angles of the needle electrode in the dry system.It is found that when the tip is placed at 90°,the flow line of dust particles is mostly close to the dust collection pole,and the ionic wind vortex near the orifice plate is smaller,which is more conducive for dust collection.Finally,on the basis of the previous studies,the corrugated-aperture plate structure is proposed.It is found that the spatial field strength can be increased in the corrugated type.The main airflow near the dust collection pole has a wider resistance area in the tapering and expanding structure.The ion wind vortex between the discharge electrodes is compressed or even disappeared,which effectively improves the dust removal efficiency. |
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