On the time coupling analysis of explosion pressure and intermediate generation for multiple flammable gases

Abstract

In this paper, the key product (CH2O) from the explosive chain reaction of methane is selected as the research object, and a method for analysing the coupling mechanism between the explosion pressure and intermediate products is proposed; this method provides a theoretical basis for the construction of an explosion control system with chemical effects. A 20-L spherical closed explosion experimental system and spectral measurement system are used to investigate the pressure and flame emission spectra characteristics of the intermediate products during the mixed explosion process of five typical gases (CH4, C2H6, C2H4, CO, and H2). The time difference (ΔT) between the peak explosion pressure (Pmax) and the peak CH2O spectral intensity is proposed to analyse the coupling relationship between them. On the one hand, the results show that ΔT reflects the effect of the improvement in CH2O generation on explosion intensity; the smaller the ΔT value is, the greater the improvement is. On the other hand, ΔT reflects the main source of CH2O; when the sample concentration is smaller, CH2O is mainly formed during the explosive chain reaction. When the sample concentration is larger, CH2O mainly originates from the bond polymerization of alkylene compounds. The effects of the system conditions (sample concentration, sample composition and methane concentration) on the ΔT and CH2O formation rates are combined, and the correlation between Pmax and ΔT can reflect the coupling mechanism between the explosion pressure and intermediate products. When the oxygen is enriched, ΔT is negatively correlated with Pmax using the power function model, with R2 > 0.95.