Generation process and sterilization effect of OH radical in a steam plasma flow at atmospheric pressure for a plasma autoclave

The reactive flow field and the mechanism of sterilization by steam plasma flow at atmospheric pressure were clarified to develop a new sterilization system by experimental and computational methods. The emission lines of OH, whose intensity increased with increased applied voltage and frequency, were observed in the discharge region. The OH radical finally changed to H₂O₂ in the condensed water. The OH radical was capable of sterilizing spores of Geobacillus stearothermophilus, although the condensed water did not have such effect. The discharge process was clarified with an axisymmetric, non-Maxwellian model. The OH radical was generated by a wire electrode toward the ground electrode, and the concentration of H₂O₂ increased after streamer propagation.