  This study investigates the correlation between flow fields induced by a
surface dielectric barrier discharge (SDBD) system and its application for the
volatile organic compound (VOC) gas conversion process. As a benchmark
molecule, the conversion of n-butane is monitored using flame ionization
detectors, while the flow field is analysed using planar particle image
velocimetry. Two individual setups are developed to facilitate both conversion
measurement and investigation of induced fluid dynamics. Varying the gap
distance between two SDBD electrode plates for three different n-butane mole
fractions reveals local peaks in relative conversion around gap distances of 16
mm to 22 mm, indicating additional spatially dependent effects. The lowest
n-butane mole fractions exhibit the highest relative conversion, while the
highest n-butane mole fraction conversion yields the greatest number of
converted molecules per unit time. Despite maintaining constant energy density,
the relative conversion exhibits a gradual decrease with increasing distances.
The results of the induced flow fields reveal distinct vortex structures at the
top and bottom electrodes, which evolve in size and shape as the gap distances
increase. These vortices exhibit gas velocity magnitudes approximately seven
times higher than the applied external gas flow velocity. Vorticity and
turbulent kinetic energy analyses provide insights into these structures'
characteristics and their impact on gas mixing. A comparison of line profiles
through the centre of the vortices shows peaks in the middle gap region for the
same gap distances, correlating with the observed peaks in conversion. These
findings demonstrate a correlation between induced flow dynamics and the gas
conversion process, bridging plasma actuator studies with the domain of
chemical plasma gas conversion.
