Quantify the slow decay of relative VOC conversion with increasing SDBD gap distance

Quantify the slow decay of relative n-butane conversion as the gap distance between two opposing surface dielectric barrier discharge electrodes increases under constant energy density and constant inlet gas velocity, and determine which additional factors contribute to this behavior.

Background

The study investigates n-butane conversion in air using two opposing surface dielectric barrier discharge (SDBD) electrodes while varying the electrode gap distance. The energy density is kept constant and the inlet flow velocity is held fixed to isolate flow-field effects on conversion. The authors observe a gradual decrease in relative conversion with increasing gap distance, with local maxima near 16–22 mm.

Particle image velocimetry shows vortex structures whose integrated absolute vorticity in the center of the gap decays more rapidly with distance than the measured conversion. Although increased repetition frequency raises overall vorticity at larger gaps, it does not fully account for the observed conversion behavior, leading the authors to state that the slow decay of conversion cannot yet be fully quantified and may involve additional factors.