Premixed Combustion of Diluted Hydrogen-Air Mixtures in a Constant Volume Bomb

Combustion characteristics of diluted hydrogen-air premixed combustion were studied in a constant volume bomb over wide ranges of diluent ratios and equivalence ratios using two kinds of diluent gases. A two-zone model was applied to calculate the heat release rate and combustion duration based on the pressure data. The study showed that, by adding diluent gas into the hydrogen-air mixture, both the combustion development duration and the combustion duration are lengthened. Increasing the diluent ratio reduces the value of the peak pressure, and the reduction is larger on the rich mixture than on the lean one. CO₂ diluent gas has greater effects on the normalized mass burning rate, the combustion development duration, and the combustion duration than nitrogen. Within the experimental range of this study, the minimum value of both the combustion development duration and the combustion duration lies within the range of ø = 1.4-1.6.