Equivalent analysis of the explosion overpressure of gasoline vapor–air mixture by using isooctane equivalence ratio

Isooctane is often used as a substitute to investigate the heat release, chemical kinetic models and flame behaviors of the gasoline vapor explosion process. Such substitution always leads to some inevitable errors between the overpressures of theoretical calculation value and the experimental data of the gasoline vapor explosion. Based on the deduction of the relationship between the equivalence ratio ( ∅ ) and volume concentration of isooctane–air mixture, the constant volume adiabatic combustion temperature and overpressure of the isooctane explosion at different ∅ were calculated by using the first law of thermodynamics. Then, through the experiments of gasoline vapor explosion in a standard 20-L spherical explosive device, explosion overpressures at different gasoline vapor volume concentrations were obtained. By analyzing the overpressure error between the theoretical value of the isooctane explosion and the experimental data of the gasoline vapor explosion, an equivalent relationship in terms of isooctane equivalence ratio for gasoline vapor constant volume explosion overpressure is proposed. This relationship not only can be used to accurately predict gasoline vapor constant volume explosion overpressure by means of isooctane, but also can be used to modify the gasoline explosion overpressure calculation model and enable the errors between the model’s calculation value and the actual experimental value to be significantly reduced.