Charging and discharging of particles on the low-potential electrode under bipolar corona conditions

Abstract

In this work, the process of charging and discharging of aerosol particles on the surface of a low-potential electrode and their behaviour depending on the charge that they have are investigated under bipolar corona conditions. A general expression to characterize the kinetics of charging of these particles is developed so that this expression yields many of the special equations that have been reported in the literature and are valid under certain conditions. It is found that the intensity of the corona discharging field affects both the amount of stable charge on the particle and its charging time; in general, the time constant for discharging and the coefficient of bipolarity determine the amount of stable charge. The obtained results indicate that, under suitable conditions, use of a bipolar corona field can be an alternative technique for cleaning and refining impure aerosol mixtures for desired purposes.

Combined kinetic charging of particles on the precipitating electrode in a corona field

“…In equations ( 20a)-(20d), τ is determined by equation (7). Equation (18), which characterizes the combined kinetic charging (contact and field) of the particle on the precipitating electrode, is structurally identical to equation (17), which characterizes the field charging kinetics. But, if we compare equation ( 19) with (20) and equation (19d) with (20d), it is obvious that the parameters of equation ( 18) are different from those in equation (17).…”

“…The charging kinetics of aerosol particles on the precipitating electrode in a corona field has been investigated in assorted studies [16,18,19] elaborately. It has been demonstrated in these studies that the electrical charge of the particle in the corona field is determined by these two simultaneous processes: (i) charging of the ions from the corona field of the particle and (ii) discharging of the charged particle on to the contacting surface.…”

“…As a result, if the intensity of the corona discharging in a charging process does not change and the radii of the particles are larger than ∼3 µm (r p > 3 µm), by using equation ( 1), the differential equation determining the charging kinetics of the particles on a precipitating electrode for the conditions of a unipolar corona field can be expressed as [18]…”

“…Currently, the most widely used method in charging particles in EIT is the charging of the particles in a volume charged electrical field or charging by high voltage electrode contact [15][16][17][18][19][20]. As is well known, charging of the particles in a volume charged electrical field consists of these two 3 Author to whom any correspondence should be addressed.…”

Calculation of electrical field of spherical and cylindrical gas voids in dielectrics by taking surface conductivity into consideration

“…The voids occurring in the structure of homogeneous dielectric because of technological causes can destroy the electrical field in dielectric. Generally, we face with these kinds of problems in contact charging processes of particles on high‐voltage electrode in electron‐ion technology and in the analysis of ionization processes and mechanisms of gas voids in the structure of insulator, in the dielectric separation process (Hinds, 1999; Zhuang et al , 2000; Aliyev et al , 1998; Alisoy et al , 2004b).…”