Application of Plasma Assisted Vertical Jet Flame to the Ignition of Horizontal Methane-Air Mixture 吴文伟 等离子体所

BACKGROUND Stable combustion under the high flow rate Lean Flammability Limit Blowout Plasma assisted combustion

BACKGROUND Non-premixedPremixed Deficiency in reaction improvement excessive energy consumption instability of discharge Two Categories Y. Kim et la. Effect of Plasma Chemistry on Activated Propane/Air Flames. IEEE Trans. Plasma Sci., vol. 34, no. 6, Dec. 2006

THE EXPERIMENTAL SETUP Parameters: Power: 100 W Frequency: 5 kHz Flow rate of vertical air (Ver(air)): 20 slm Flow rate of vertical CH 4 (Ver(CH 4 )): 0-3 slm α=Ver(CH 4 )/Ver(air) Flow rate of horizontal air (Hor(air)): slm Flow rate of horizontal CH 4 (Hor(CH 4 )): 0-8 slm

I. THE SPECTROSCOPY OF THE JET FLAME OH intensity is lowest at stoichiometric condition, relative higher under lean and rich condition Ver(air) : 20 slm Ver(CH 4 ) : 0-3 slm α: Hor(air): 0 slm Hor(CH 4 ): 0 slm α=0.02 α=0.13α=0.1 α=0.06 Stoichiometric rate

II. THE GASEOUS PRODUCT OF THE JET FLAME With plasma on: Lean flammability limit of jet flame is extended; More H 2 and CO generated with higher equivalence ratio No flame without plasma Cannot combust in the tube without plasma Stoichiometric rate Ver(air) : 20 slm Ver(CH 4 ) : 0-3 slm α: Hor(air): 0 slm Hor(CH 4 ): 0 slm

III. STABILITY OF JET FLAME α=0.05 α=0.13α=0.15 Lower α: Higher methane oxidation efficiency Higher α: No blowout Ver(air) : 20 slm Ver(CH 4 ) : 0-3 slm α: Hor(CH 4 ): 0 slm Hor(air): slm α=0.1 With plasma on:

IV. LEAN FLAMMABILITY LIMIT α=0 Lean flammability limit is extended by plasma More obvious for low or high α than the stoichiometric condition Ver(air) : 20 slm Ver(CH 4 ) : 0-3 slm α: Hor(CH 4 ): 0-8 slm Hor(air): 100 slm α=0.15α=0.1 α=0.03 Stoichiometric rate

SUMMARY: I. The emission intensities of active radicals in the jet flame II. The gaseous product of the jet flame III. The stability of the jet flame IV. The lean flammability limit of the integral combustion

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