Dominant heating mechanisms in a surface barrier discharge

Abstract

In computational models of atmospheric pressure surface barrier discharges (SBDs) the role of heating of the dielectric material and the quiescent gas is often neglected, impacting the accuracy of the calculated chemical kinetics. In this contribution, a two-dimensional fluid model of an SBD was developed and experimentally validated to determine the relative contribution of the dominant heat transfer mechanisms and to quantify the impact of discharge heating on the resultant chemistry. Three heating mechanisms were examined, including electron heating of the background gas due to inelastic collisions, ion bombardment of the dielectric surface and dielectric heating by the time-varying electric field. It was shown that electron heating of the background gas was not significant enough to account for the experimentally observed increase in temperature of the dielectric material, despite being the dominant heating mechanism of the gas close to the electrode. Dielectric heating was ruled out as the frequency response of typical dielectric materials used in SBD devices does not overlap with the experimentally observed power spectrum of an SBD excited at kHz frequencies. The ionic flux heating was found to be the dominant heating mechanism of the dielectric material and the downstream flow driven by the SBD. The largest impact of plasma heating on discharge chemistry was found in reactive nitrogen species (RNS) production, where the densities of RNSs increased when an appropriate treatment of heating was adopted. This had a marked effect on the discharge chemistry, with the concentration of NO2 increasing by almost 50% compared to the idealized constant temperature case.

Surface temperature characterization of dielectric barrier discharge plasma actuator in quiescent air

“…Tirumala et al hypothesized that Joule heating is the dominant heating mechanism, which has been experimentally demonstrated [27]. However, some studies have suggested that ion flux heating is not negligible [32,33]. Thus, the details of the heating mechanism of the DBDPA are still disputed.…”

Mutual interaction among multiple surface barrier discharges

“…To investigate the interaction between neighbouring discharge gaps in an SBD array, a numerical model developed in previous works by the authors, [25][26][27] was modified to havesixadjacent discharge gaps instead of one. A one-discharge model was experimentally validated in terms of fluid dynamics, [25,27] heat transfer [26] and chemistry.…”

“…To investigate the interaction between neighbouring discharge gaps in an SBD array, a numerical model developed in previous works by the authors, [25][26][27] was modified to havesixadjacent discharge gaps instead of one. A one-discharge model was experimentally validated in terms of fluid dynamics, [25,27] heat transfer [26] and chemistry. [27] To validate the extended model's ability to capture emerging behaviour among neighbouring discharge gaps, particle image velocimetry (PIV) was used to measure the velocity field close to the electrodes, providing supporting evidence to the validity of the model.…”

Microdischarge dynamics of volume DBD under the natural convection airflow

“…Few studies have been focused on the research of heat transfer, including natural convection in a surface dielectric barrier discharge [23]. The simulation model in conjunction with experimental investigation was employed to ascertain the function of the primary heat transfer mechanisms and to measure the impact of discharge-generated heat on the resulting chemical reactions.…”