On the influence of electronically excited oxygen molecules on combustion of hydrogen–oxygen mixture

Abstract

This communication reports on the experimental observation of the shortening of the induction zone length in a premixed mode of combustion in a subsonic H2–O2 low pressure flow due to the presence of oxygen molecules excited to the singlet a 1Δg electronic state. The low pressure electric glow discharge was used to produce singlet oxygen molecules. The analysis showed that even a small number of O2(a 1Δg) molecules (∼1%) in the H2–O2 mixture allows one to noticeably reduce the ignition delay length and to ignite the mixture at a lower temperature. The results obtained exhibit the possibility to intensify the combustion of a hydrogen–oxygen mixture by means of excitation of O2 molecules by electrical discharge at low pressure (P = 10–20 Torr).

The effects of hydrodynamic stretch on the flame propagation enhancement of ethylene by addition of ozone

“…Gao et al [32] showed that at higher pressures or at longer residence times, this is no longer the case, but at reduced pressures and the flow residence times in the current experiments, the reaction between the two is negligible. In addition, other works have noted that reactions between O 3 and saturated hydrocarbons such as CH 4 are quite slow at room temperature, and therefore the influence of O 3 on such fuels can be ignored [20]. Although the addition of reactions in the O 3 sub-mechanism does not consider synergistic effects, or how the addition of these reactions affects the rates of reactions present in the original mechanism, good agreement has been found between experimental results and the simulations [19,20,22].…”

“…Vu et al showed that for CH 4 at 101 kPa, the dominant pathway can change depending on the equivalence ratio, with (3.1) dominant at stoichiometric conditions but (3.2) dominant at lean and rich conditions [21]. Additionally, pressure effects have been observed for stoichiometric CH 4 where (3.2) becomes dominant over (3.1) above approximately 140 kPa [32].…”

Plasma-Assisted Ignition and Combustion

“…A numerical study of the plasma assisted ignition of hydrogen-oxygen mixtures at different E/n has been performed in . Results at low E/n values are compared with experimental data [Smirnov et al, 2008] and good agreement between experimental and numerical data was demonstrated. It was shown that the efficiency of radicals production through the oxygen singlet states excitation is limited by collisional quenching of SDO molecules in oxygen-fuel mixtures; in oxygen-nitrogen mixtures main efficiency limitation comes from discharge energy flux alternation by vibrational excitation of nitrogen (see also Figure 17,b).…”

“…Singled oxygen molecules as a tool for ignition and combustion control were proposed by group of Starik [Smirnov et al, 2008]. The effect of the excitation of oxygen molecules to the O 2 (a 1  g ) and O 2 (b 1  g + ) electronic states in the electrical discharge on the velocity of laminar flame propagation in the H 2 -O 2 mixture was analyzed.…”

“…Later the same team proposed to use a laser radiation at λ = 762.346 nm for O 2 molecules excitation to the b 1  g + electronic state. Experimental observation of the shortening of the induction zone length in a premixed mode of combustion in a subsonic H 2 -O 2 low pressure flow due to the presence of oxygen molecules excited to the singlet a 1  g electronic state was reported in [Smirnov et al, 2008]. The low pressure electric glow discharge was used to produce singlet oxygen molecules.…”