Hypersonic MW ignition.PPT

Plasma Assisted Ignition and Combustion S.M.Starikovskaia, A.Yu.Starikovskii Plan of the Talk “Fast flow” ignition (Mintoussov, Starikovskii, 2005) Plasma: equilibrium or nonequilibrium? Scheme of H2-O2 Combustion Comparison of the Reaction Rates Possible Mechanisms for PAI/PAC Complexity of the object Scheme 1a: Discharge + Flow, Quasistationary System Hypersonic MW ignition Hypersonic MW ignition Scheme 1b: Discharge + Flow, Quasistationary System Discharge Development in the Gas Flow.U = 25 kV, timp = 25 ns, Propane-Air, f = 0.7 Bluff-body nozzle with ns discharge Discharge enhanced flame stabilization Ignition of a gas flow by RF discharge Scheme 2 (PAI): pulsed discharge + ignition. No flow! 3) Volume repetitive nanosecond discharge Typical behavior of electric field How does it works: decrease of ignition delay time (PAI) Comparison of experiments and numerical modeling: CH4-C5H12 mixtures Kinetics of Plasma Assisted Ignition at Elevated Temperatures S.M.Starikovskaia, N.L.Aleksandrov, S.V.Kindusheva, I.N.Kosarev, A.Yu.Starikovskii Experimental setup for plasma ignition Setup for nanosecond Electrical Measurements Scheme of the experiment Parameters Varied in Experiments Mixture composition CH4/C2H6/C3H8/C4H10/C5H12 - O2 – Ar (90%) Temperature 950-2000 K Pressure 0.2-1.0 atm Parameters Controlled in Experiments Velocity of the Shock Wave (T5, P5) IR Emission of CO2 at 4.21 mm (T5) Emission of OH at 306 nm (tign) Emisison of CH at 431 nm (tign) Distribution of potential along the gap (E/N) Electrical current (energy input) Shift of the ignition delay time Particles, responsible for Ignition, are… Typical evolution of electric field and current (CH4:O2:Ar; T5=1450 K, n5=6x1018 cm-3) The peak E/n for C2H6-C5H12-containing mixtures Specific energy input Composition of the mixtures Scheme of the Discharge Description Typical densities of active species produced by the discharge vs E/n: C2H6, C5H12 Kinetics in the discharge Densities