Investigating Flow-Induced Changes in Coaxial Cylindrical Dielectric Barrier Discharge Using Equivalent Circuit Modelling and Chemical Workbench Simulations

This study presents the development of an equivalent electrical circuit model using MATLAB/Simulink to simulate the discharge behaviour of a coaxial cylindrical dielectric barrier discharge (DBD) and explores the influence of the flow regime on its electrical characteristics. Validation of the experimental findings was performed using Simulink and Chemical Workbench (CWB). The simulations provided valuable insights into the DBD behaviour, facilitating its performance optimization. The equivalent circuit model demonstrated accurate predictions of peak current amplitude \((I_{peak} )\), root mean square of total current \(\left( { I_{rms } } \right)\), and microfilament discharge resistance \(\left( { R_{f } } \right)\). The study unveiled a significant impact of the flow regime on the electrical properties of the DBD. As the flow rate (Q) transitioned from the laminar flow regime (Reynolds number, Re = 300) to the turbulent flow regime (Re = 4500), the peak current \((I_{peak} )\) exhibited an increase from 60 to 80 mA for Argon (Ar) and 90–140 mA for Nitrogen (N₂) gas. Simultaneously, the \(R_{f }\) decreased from 3.0 to 0.6 mΩ for Ar and 2.0 mΩ to 0.1 mΩ for N₂. The effect of Q on discharge mode was analyzed using image analysis. In N₂, the discharge remained more filamentary across a wider range of Q (from 5.8 to 31.5 SLPM) compared to Ar. Electron density (n_e) estimated from both experimental data and the CWB model, was found to be of the same order of magnitude. For both gases, an increase in Q led to a rise in n_e and a reduction in \(R_{f}\). Even at higher Q, the filamentary structure in N₂ was more persistent compared to Ar. The effect of Q on gas temperature (\(T_{g }\)) was also studied, showing a decrease in \(T_{g }\) for both Ar and N₂, from 408 to 320 K for Ar and from 689 to 435 K for N₂, corresponding to increased Q under identical conditions. The impact of the flow regime on \(R_{f }\) was analyzed using the Peclet number (Pe) to gain a better understanding of heat/mass transport from the discharge to the surroundings. The MATLAB/Simulink and CWB models corroborated these findings, demonstrating excellent agreement with the experimental results. This validation underscores the reliability of the models in effectively characterizing the discharge parameters of the DBD.