High-efficiency ozone generation using a multi‑chamber coaxial dielectric barrier discharge system for water treatment

This paper presents the design, modeling, and experimental evaluation of a multi-chamber coaxial Dielectric Barrier Discharge (DBD) reactor for enhanced ozone generation in water-treatment applications. The proposed reactor employs axially staged discharge chambers to increase effective ionization volume without increasing local electric-field stress. Finite-element simulations confirm strong electric-field localization within the 1-mm air gap, achieving peak intensities up to 145 kV/cm at 15 kV while preserving dielectric integrity. Experiments were conducted at applied voltages of 5–15 kV, airflow velocities of 2 m/s and 5 m/s, and treatment durations up to 10 minutes. Ozonation performance was evaluated using CIE Lab* colorimetric analysis. Results show that higher applied voltage significantly enhances chromatic degradation due to intensified ionization activity. Lower airflow velocity (2 m/s) improves ozone utilization by extending residence time, while increasing the chamber count from one to three chambers enables cumulative plasma exposure and near-complete decolorization under optimal conditions (15 kV, 2 m/s). Power analysis reveals increased electrical consumption with additional chambers, indicating a performance–energy trade-off. Energy-normalized evaluation demonstrates that although total decolorization increases, efficiency per unit power decreases slightly. The estimated ozone production rate for the three-chamber configuration at 15 kV ranges from 0.8 to 4.8 g/h. The proposed staged architecture provides a scalable strategy for balancing ozone output and energy efficiency.