高水平等离子体能量耦合预混火焰中氮氧化物生成
This paper presents quantitative planar laserinducedfluorescence (PLIF) imaging of nitric oxide (NO) in atransient-arc direct-current plasmatron igniter using premixedair/fuel mixtures. Quantitative measurements of NO are reportedas a function of gas flow rate (20–50 standard cubic feet perhour), plasma power (100–900 mA, 150–750 W), and equivalenceratio (0.7–1.3). Images were corrected for temperature effects byusing 2-D temperature field measurements obtained with infraredthermometry and calibrated by a more accurate multiline fittingtechnique. The signals were then quantified using an NO additionmethod and spectroscopic laser-induced fluorescence modelingof NO. NO PLIF images and single-point NO concentrationsare presented for both plasma-discharge-only and methane/airplasma-enhanced combustion cases. NO formation occurs predominantlythrough N2(v) + O → NO + N for the plasmadischarge-only case without combustion. The NO concentrationfor the plasma-enhanced combustion case (500–3500 ppm) wasan order of magnitude less than the plasma-discharge-only case(8000–15 000 ppm) due to the reduction of plasma reactions by themethane. Experiments show the linear decay of NO from equivalenceratio 0.8–1.2 under the same flow condition and dischargecurrent.Index Terms—Nitric oxide (NO), plasma torch, plasma-assistedcombustion.