Fast gas heating of nanosecond pulsed surface dielectric barrier discharge: spatial distribution and fractional contribution from kinetics

2018 ◽  
Vol 27 (12) ◽  
pp. 124007 ◽  
Author(s):  
Yifei Zhu ◽  
Svetlana Starikovskaia
Author(s):  
M. M Nudnova ◽  
S. V Kindysheva ◽  
N. L Aleksandrov ◽  
A. Yu Starikovskii

The fractional electron power quickly transferred to heat in non-equilibrium plasmas was studied experimentally and theoretically in N 2 /O 2 mixtures subjected to high electric fields. Measurements were performed in and after a nanosecond surface dielectric barrier discharge at various (300–750 Torr) gas pressures and (50–100%) N 2 percentages. Observations showed that the efficiency of fast gas heating is almost independent of pressure and becomes more profound when the fraction of O 2 in N 2 /O 2 mixtures increases. The processes that contribute towards the fast transfer of electron energy to thermal energy were numerically simulated under the conditions considered. Calculations were compared with measurements and the main channels of fast gas heating were analysed at the gas pressures, compositions and electric fields under study. It was shown that efficient fast gas heating in the mixtures with high fraction of O 2 is due to a notable contribution of heat release during quenching of electronically excited N 2 states in collisions with O 2 molecules and to ion–ion recombination. The effect of hydrocarbon addition to air on fast gas heating was numerically estimated. It was concluded that the fractional electron power transferred to heat in air, as a first approximation, could be used to estimate this effect in lean and stoichiometric hydrocarbon–air mixtures.


Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3933 ◽  
Author(s):  
Shen Zhang ◽  
Zhenli Chen ◽  
Binqian Zhang ◽  
Yingchun Chen

In order to understand the impacts of dielectric barrier on the discharge characteristics of a nanosecond pulsed surface dielectric barrier discharge (NS-DBD), the effects of dielectric constant and dielectric barrier thickness are numerically investigated by using a three-equation drift–diffusion model with a 4-species 4-reaction air chemistry. When the dielectric constant increases, while the dielectric barrier thickness is fixed, the streamer propagation speed (V), the maximum streamer length (L), the discharge energy ( Q D _ e i ), and the gas heating ( Q G H ) of a pulse increase, but the plasma sheath thickness (h), the fast gas heating efficiency η , and the charge densities on the wall surface decrease. When the dielectric barrier thickness increases, while the dielectric constant is fixed, V, L, Q D _ e i , and Q G H of a pulse decrease, but h, η , and the charge densities on the wall surface increase. It can be concluded that the increase of the dielectric constant or the decrease of the dielectric barrier thickness results in the increase of the capacitance of the dielectric barrier, which enhances the discharge intensity. Increasing the dielectric constant and thinning the dielectric barrier layer improve the performance of the NS-DBD actuators.


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