Role of the wall reactor material on the species density distributions in an N2–O2post-discharge for plasma sterilization

The species density distributions in a large post-discharge reactor placed downstream from a flowing microwave discharge in N 2 –O 2 are calculated using a three-dimensional hydrodynamic model. The effects of surface losses of N( 4 S) and O( 3 P) atoms on the density distributions of different species in the reactor are investigated for three different wall materials: (i) Pyrex, (ii) aluminium and (iii) stainless steel. The effects produced by considering different surface loss probabilities corresponding to each one of these materials, as well as by assuming the production of NO from the wall, are evaluated and discussed. The simulation is conducted for the case of a 65 × 25 × 25 cm 3 post-discharge reactor fed from a 2450 MHz discharge, at 2 Torr and 2 × 10 3 sccm flow rate, in an N 2 – x O 2 mixture composition, with x = 0.5–7%.