Experimental determination and numerical evaluation under simplifying assumptions of the ozone concentration in an atmospheric-pressure air DBD plasma

摘要

In this work ozone concentration in a plane-to-plane Dielectric Barrier Discharge (DBD) reactor has been evaluated both experimentally and numerically. The reactor geometry has been chosen to generate a homogenous discharge. Therefore, simplified approaches for both experiments and numerical simulations have been utilized. The discharge was excited for 20 s in atmospheric-pressure quiescent air by means of a sinusoidal voltage of 15 kV peak at a frequency of 5 kHz in continuous operation. Electrical and optical measurements have been done to estimate the input parameters for the kinetics model. The ozone density within the discharge gap was measured by using the UV absorption method. The optical path travelled by the UV beam inside the reactor gap was estimated by means of Schlieren imaging. Within the time intervals and the dimensions considered, plasma was assumed to be uniform. This assumption was confirmed experimentally by iCCD images of the discharge. Numerical simulations have been performed by means of the zero-dimensional open-source code ZDPlasKin. A set of 622 reactions among 62 chemical species has been implemented, accounting for a 1% water vapour fraction. Reduced electric field, electron density and gas temperature were the input parameters of the code. Ozone density presented a production peak of about 1.3.10(17) cm(-3) half a second after discharge ignition. A steady state value of 6.10(16) cm(-3) was reached after a transient of about 12 s. Numerical simulation delivered ozone concentrations in good agreement with experimental data.