Design and restrictions on spherical jet-stirred plasma reactor

This work explores the design and the limitation of new spherical plasma reactor using the Concentric Inlet And Outlet geometry (CIAO) applying the Nanosecond Repetitively Pulsed Discharge. Two electrode placements are investigated, center ball and the end ball geometries. First, four discharge regions, namely no discharge, corona, glow discharge and arc discharge regions are identified with varying voltage and pressure where Paschen curve-like diagram is presented. The repetitive frequencies do not seem to greatly alter the boundaries of discharge region of which only the glow discharge region become smaller as the frequency increases. Second, we investigate the limitation of the CIAO design based on pressure p and residence time t and identify four possible limitations, vacuum, discharge, chemical reaction time and mixing limitations. To achieve uniform glow discharge, operation pressure are set to be at around 0.2 atm leading to low Reynolds number (Re). We conducted numerical simulations at Re=50 to accommodate the operation at low pressure with the consideration of the presence of electrode in the center which have not yet been investigated before. We also measure the location of glow discharge of two electrode placements and redesign the reactor geometry based on plasma discharges. Results show what our CIAO design preforms reasonably well under extreme low Re and demonstrates the potential of spherical jet-stirred plasma reactor.