ELECTROSTATIC FIELD IN A BARRIER DISCHARGE CHAMBER FOR WATER PURIFICATION CONSIDERING INDIVIDUAL WATER DROPLETS

The use of pulsed dielectric barrier discharge (DBD) for water purification via low-temperature plasma (LTP) is a promising technology. DBD enables the purification of water in a droplet-film state from organic contaminants by generating highly reactive molecules (OH radicals, O, H2O2, and O3 molecules) produced in LTP upon contact with water. A two-dimensional model was developed to calculate the electrostatic field in the DBD discharge chamber (DC), which includes two electrodes, a dielectric barrier, two water droplets or streams in the air gap, and water films. The model employs Laplace’s equation for the electrostatic field with periodic boundary conditions. Expressions were proposed for determining the length of the symmetric part of the DC and setting the voltage on the electrodes with a constant droplet surface area and a constant average electric field intensity in the air gap, independent of droplet radius. The study investigates the dependence of the electrostatic field energy and DC capacitance on the droplet radius and their mutual positioning along the DC length. Changes in electrode voltage and droplet density per unit DC length relative to droplet radius are demonstrated. An analysis of the electric field distribution, DC capacitance, and stored energy was conducted. The average electric field intensity on the surfaces of droplets and water films was examined. The electric forces acting on the droplets were determined using Maxwell's stress tensor. An expression was derived for calculating the recommended amount of water in the form of droplets or streams per unit dimensions of the DC to achieve a more uniform distribution of the electric field intensity within the DC and to minimize the impact of electric forces on the droplets. Ref. 18, fig. 7.