Interaction of Plasma Discharges with a Flame: Experimental and Numerical Study

This paper presents experimental results and numerical simulations of methane/air non-premixed flame under plasma assistance. Without plasma assistance, the flame blows off at a 28-30 m.s(-1) bulk velocity (power around 3 kW). When the discharge is on, the flame can be maintained up to a bulk velocity of 53 m.s(-1) (power around 6 kW), corresponding to +90% gain in power with only a few watt of plasma power. The plasma discharges present short duration current pulses (between 100 ns and 200 ns) and occur non-monotonically (delay between two pulses from 6x10(-5) s to 0.1 s). The probability density function of this occurrence is significantly influenced by the mass flow rate or the absence of flame, revealing the strong coupling of the plasma with hydrodynamic and combustion. For the numerical section of this work, we simulated the flame using a Computational Fluid Dynamics code based on Direct Numerical Simulation (direct solving of Navier-Stokes equations), and investigated the thermal and/or chemical effects of discharges on the flame stability.