A macroscopic and microscopic study of hydrogen-rich explosions under inert gas conditions

Using nearly 20L explosive ball, the effects of various N2 and CO2 ratios (5%, 10%, 15%, and 20%) on the explosion characteristics of hydrogen-rich mixtures were studied. The transient emission spectral intensities of H*, OH*, and O* were simultaneously collected in order to compare the influence laws of inert gas on hydrogen explosion from both macroscopic and microscopic aspects. Using the Fundamental Fuel Chemistry Model (FFCM2), the thermodynamic parameters and exothermic pattern of the reaction were also computed and analyzed. The results are as follows: When the proportion of N2 is greater than 10%, the explosion pressure rise rate (dp/dt)max is inhibited more clearly; CO2 has a greater effect than N2 on the maximum explosion pressure Pmax and (dp/ dt)max of the high equivalency ratio hydrogen explosion; under N2, the accumulation of free radicals OH* is greater than that of H* and O*; the reduction of the peak radiation signal intensity Imax is significantly greater than the effect of Pmax; and CO2 has a greater effect than N2 on the adiabatic flame temperature AFT and thermal diffusivity alpha. CO2 had a considerably stronger inhibitory effect than N2 on both alpha and AFT.