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 CH 2 O* 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 C 2 H 4 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 C 2 H 4 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 C 2 H 4 , directly results in a change in the average rising rate and maximum emission intensity of the intermediates.