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This paper presents the results of an experimental investigation of corona discharge in Wire-to-Plane Electrostatic Precipitator (WP-ESP). The influence of relative humidity level (RH) on the collection efficiency of a WP-ESP is analyzed. Experimental investigations of the humidity effect on corona discharge in electrostatic precipitator are of interest for the interpretation of electrical conduction and collection efficiency phenomena in high electric fields. The experiments were performed with incense smoke particles having a mean size of about 0.28 µm. An aerosol spectrometer was employed for characterizing the size distribution of these particles at the outlet of the ESP. Then, the collection efficiencies were measured for relative humidity levels of 40 and 70%. Various DC applied voltages in the case of positive and negative polarities have been under consideration. For given atmospheric conditions, the results obtained with the aerosol spectrometer show that the performance of the ESP increases with the applied voltage (range: 10-40 kV). Also, the collection efficiency is higher at increased RH. The negative corona discharge is overall more effective than the positive one. However, the difference between the two polarities becomes minor at high RH. The performances of the ESP are improved at elevated humidity probably due to the enhancement of the particle charging in the inter-electrode gap on one hand, and the particle cohesivity on the collecting electrodes on the other hand. [ABSTRACT FROM AUTHOR]

In this paper, the interaction between a dielectric barrier discharge and submicron particles is investigated experimentally using Laser Doppler Velocimetry (LDV) and Particle Image Velocimetry (PIV) techniques in a wire-to-plane configuration. The induced electrohydrodynamic (EHD) phenomena have been studied by time-averaged and time-resolved measurements for different AC high voltage waveforms. The main results indicate that the particle time-averaged velocity increases with the HV frequency whatever the measurement position due to electric wind effect. The time-resolved velocity increases during both positive and negative discharges inducing a strongly non-stationary EHD flow. After the propagation of streamers, a reduction of the particle number in the gap is observed at low frequency due to particle charging and electrostatic precipitation by the electric field. [ABSTRACT FROM AUTHOR]

Abstract: This paper aims at characterizing the behavior of dc corona discharge in wire-to-plane electrostatic precipitators (ESPs) as influenced by the relative humidity (RH) of the inlet air. The current–voltage characteristics and time evolution of the current are analyzed. Experimental results show that discharge current is strongly affected by the RH level of the inlet air. For instance, the time-averaged current is lower at higher RH for a given voltage, except when RH = 99%. Time evolution of the discharge current is affected by the humidity especially in the case of negative corona. [Copyright &y& Elsevier]

The aim of the present work has been to quantify the efficiency of Dielectric Barrier Discharges (DBDs) for the collection of submicron particles. The experiments were performed with incense smoke particles having a mean size of about 0.3 μm. An aerosol spectrometer was employed for characterizing the size distribution of these particles at the outlet of Wire-to-Cylinder (WC) and Plate-to-Plate (PP) DBD reactors. The collection efficiency was estimated for various applied voltages (6 - 26 kV, 1 - 2000 Hz), and airflow rates of 1.6 - 24 L/min. The discharge mode was diffuse, in the case of the axisymmetric configuration, and filamentary, in the case of the planar configuration. When flow rate increases, the discharge current and the electric power decrease in both cases. This effect is less pronounced with the planar configuration. Results obtained with the aerosol spectrometer show that the particle collection efficiency of both reactors is higher at high applied voltage and low flow rate; it decreases at high frequency because of particle oscillations, and at low frequency due to the intermittent nature of the discharge. The frequency range for which the collection efficiency is higher than 90% is wider in the case of WC reactor. [ABSTRACT FROM AUTHOR]

The treatment of diesel particle deposit, using a surface dielectric barrier discharge, is investigated. Main results show that, in the presence of diesel particle deposit, discharge current and averaged electric power decrease gradually with the treatment duration. During the treatment process, the microdischarges are intense locally. At the end of the treatment, the discharge behavior is similar to the one obtained with a clean dielectric surface. [ABSTRACT FROM AUTHOR]