Vibration-to-translation energy transfer in atmospheric-pressure streamer discharge in dry and humid air

Vibration-to-translation (V-T) energy transfer in atmospheric-pressure streamer discharge is numerically simulated using a two-dimensional electro-hydrodynamic model. The model includes state-to-state vibrational kinetics in humid air and is coupled with the compressible flow equation of the gas fluid. The vibrational distribution of O-2(v) reaches equilibrium more quickly than that of N-2(v), whereas the energy released from O-2(v) does not increase the gas temperature. In humid air, the decay rate of the vibrational energy of N-2(v) is accelerated by the V-T energy transfer through water molecules and the energy heats the gas. However, the increase in gas temperature due to V-T energy transfer is not always seen because it competes with thermal diffusion.