Large eddy simulation of plasma-assisted ignition and combustion in a coaxial jet combustor

摘要

To study the effect of plasma O_3 on the combustion-supporting process for a coaxial jet combustor, large eddy simulation (LES)-partially stirred reactor (PaSR) simulation of a methane/air turbulent diffusion combustion was carried out based on OpenFOAM open-source software platform. The prediction of the turbulent diffusion flame was verified, and the results are in good agreement with the experiment data. Then the effect of air discharge product (i.e., O_3) on the methane ignition and combustion process was investigated using plasma-assisted combustion model by 341 steps detailed reaction mechanism. The results show that the addition of O_3 can increase the speed of flame propagation and accelerate the ignition process of methane combustion. It is also found that the vortex structure with O_3 is more continuous in the recirculation zone, and the flame recirculation zone with O_3 is closer to the inlet. The effect of O_3 on enhanced combustion is more obvious in the low-temperature region, while the axial-velocity ratio with O_3 is considerably improved in the high-temperature region. Besides, the plasma O_3 will reduce the fluctuation of v_x'v_x', especially at the peak point, which will tend to stabilize the recirculation zone.