Reactor modeling for designing and optimizing dielectric barrier discharge reactors for CO₂ splitting: Parametrization of electrical and thermal effects

Advanced reactor modeling of dielectric barrier discharge (DBD) reactors for CO₂ splitting is crucial for their optimized design and scale-up. It requires simplified yet physically interpretable descriptors that link electrical behavior, thermal effects, and operating conditions under steady-state conditions. In this work, the electrical and thermal response of a coaxial DBD reactor for CO₂ splitting was systematically investigated over a wide range of operating powers, reactor geometries, and gas flow rates (6–40 W, 5–10 cm reactor length, 0.08–0.13 cm discharge gap, 20–100 mL·min⁻¹). Key gas-related electrical parameters, including gas resistance, kinetic inductance, and gas capacitance, were experimentally evaluated using an equivalent-circuit-based analysis and interpreted alongside gas temperature distributions and microdischarge activity. Rather than resolving individual discharge events, the proposed approach provides a reduced-order steady-state parametrization of the dominant electrical and thermal features governing reactor behavior, yielding an advanced yet manageable reactor model that describes the complex, mutually interacting phenomena influencing performance while allowing optimization and scale-up. Clear dependencies were observed between plasma power and reactor geometry, particularly the inner electrode diameter, discharge gap, and reactor length, indicating that electrical coupling and geometric design primarily govern the reactor response under the conditions investigated. By contrast, gas flow rate showed a comparatively weaker influence in the explored range. The resulting parametrization provides a physically grounded framework for interpreting experimental trends in CO₂-DBD reactors. It establishes a basis for future integration with reactor-scale transport analyses aimed at performance assessment and design-oriented optimization.