The Diagnosis Of Emission Spectrum Of Bi-directional Pulsed DBD At Atmospheric Pressure

In this article, the optical emission spectrum researches have been carried out in bi-directional pulsed DBD with a needle-plate electrode in N₂/H₂O mixed gas at atmospheric pressure, and the main results presented in the dissertation have been summarized as follows:1. The influences on the product process of the emission spectra of OH(A²âˆ‘→X²Î ,0-0), N₂⁺(B²âˆ‘_u⁺→X²âˆ‘_g⁺,0-0,391.4 nm) under various discharge situations. For the emission intensity of OH(A²âˆ‘→X²Î ,0-0) has been exactly gotten by subtracting the emission intensity of theΔv=+1 vibration transition band of N₂(C³Î _u→B³Î _g) from the overlapping spectra, we use the following way to get the precise emission intensity of OH (A²âˆ‘→ΠX²Î ,0-0);firstly, to obtain the relative vibration population and the vibration temperature of N₂(C,v') by the emission intensity of theΔv=-3 andΔv=-4 vibration transition band of N₂ (C³Î _u→B³Î _g), finally, the emission intensity of OH (A²âˆ‘→X²Î ,0-0) exactly obtained by subtracting the emission intensity of theΔv= +1 vibration transition band of N₂ (C³Î _u→B³Î _g) from the overlapping spectra. The results of the experiments about the effects of voltage and discharge frequency indicate that the emission intensity of OH(A²âˆ‘→X²Î ,0-0), N₂⁺ (B²âˆ‘_u⁺→X²âˆ‘_g⁺,0-0,391.4 nm) increased with the increasing discharge voltage and frequency, as well as that of N₂⁺ (B²âˆ‘_u⁺).2. The effects of O₂,Ar and He flow rate on the emission intensities of OH (A²âˆ‘→X²Î , 0-0),N₂⁺(B²âˆ‘_u⁺→X²âˆ‘_g⁺,0-0,391.4 nm), and the vibrational temperature of N₂ (C) are investigated. It is found that the emission intensities of OH (A²âˆ‘→X²Î ,0-0) and N₂⁺(B²âˆ‘_u⁺→X²âˆ‘_g⁺,0-0,391.4 nm) decrease with increasing O₂ flow rate, but increase with the increasing flow rate of inert gases (Ar and He). The vibrational temperature of N₂ (C) increases with increasing of O₂ and He flow rate. The vibrational temperature of N₂ (C) is almost independent of the Ar flow rate and keeps nearly constant. 3. The influences of the H₂O temperature on the emission intensities of OH (A²âˆ‘→X²Î , 0-0),N₂(B²âˆ‘_u⁺→X²âˆ‘_g⁺,0-0,391.4 nm), and the vibrational temperature of N₂ (C) in DBD with a needle-plate electrode in N₂/H₂O mixed gas are investigated at atmospheric pressure. It is found that the emission intensities of OH (A²âˆ‘→X²Î ,0-0) enhance first, then decrease rapidly with the temperature increasing. The emission intensities of N₂⁺(B²âˆ‘_u⁺→X²âˆ‘_g⁺,0-0,391.4 nm) increase first, then keep nearly constant. The vibrational temperature of N₂ (C) increases with temperature increasing.4. The experimental phenomenon of the removal of formaldehyde by DBD in N₂/H₂O mixed gas at atmosphere pressure is investigated.