Atmospheric pressure plasmas penetrating through a packed-bed reactor

Atmospheric pressure micro-discharges in porous media (MDPMs) potentially play an important role in plasma assisted fuel reforming, porous material surface treatment and high efficiency NO_x removal from mobile and stationary sources. MDPMs are also of considerable interest to the biological applications of low temperature plasmas since all bio-tissues are to some degree porous media. To investigate the complex plasma-surface interactions in MDPMs, numerical simulations were performed of atmospheric pressure argon and air plasmas penetrating through an idealized packed bed reactor. The simulation platform was nonPDPSIM, a 2-dimensional plasma hydrodynamics model with radiation transport. Continuity equations for charged and neutral species, and Poisson´s equation are solved coincident with the electron energy equation with transport coefficients obtained from solutions of Boltzmann´s equation. The photon transport is based on a propagator or Green´s function method which accounts for view angles and obstructions. The idealized packed bed is 5 mm thick and placed between two planar electrodes separated by a 7 mm discharge gap. The packed bed consists of dielectric rods (ε/ε₀ = 4-400) producing a characteristic pore size of about 100 μm. The applied pulsed voltage is between 10-20 kV of either polarity.