Experimental study on the explosion and flame emission behaviors of methane-ethylene-air mixtures

Abstract

To investigate the effects of ethylene on methane-air explosions on a macro-to-micro level, the corresponding explosion and flame emission spectral behaviors were experimentally studied in a 20-L spherical chamber. The maximum explosion pressure, maximum pressure rising rate, and explosion duration were tested. The emission spectra of the key intermediates OH*, H* and CH2O* were obtained synchronously by using a photomultiplier-monochromator method. The detailed mechanism of GRI-Mech 3.0 was employed to analyze the kinetic reactions in the explosion process. A comprehensive analysis was performed by correlating the explosion parameters and emission spectral data. The results indicated that the added C2H4 would enhance the explosion of the fuel-lean methane-air mixture and attenuate the explosion of the fuel-rich mixture. It first promotes and then weakens the explosion of the stoichiometric methane-air mixture on the basis of the added volume fraction. The behavior of free radicals is well in accordance with the explosion parameters. The added C2H4 promotes the accumulation of the intermediates. Moreover, the variation in the production rate for the dominant reactions to generate the intermediates, caused by the addition of C2H4, directly results in a change in the average rising rate and maximum emission intensity of the intermediates.