Lower flammability limits of ethanol, acetone and ethyl acetate vapor mixtures in air

This work is aimed at investigating the lower flammability limits (LFLs) of ethanol, acetone, and ethyl acetate vapor mixtures in air with various mole fractions. The LFLs were measured by a self-made experimental apparatus. Besides, a theoretical calculation model of LFL based on adiabatic constant pressure was established. The heat release, adiabatic flame temperature and the sensitivity of mass burning rate on LFL are analyzed. The results indicated that as the mole fraction of a single substance in a binary mixture or a ternary mixture increases, the LFL changes monotonically. The calculated LFLs are in good agreement with the experiment. The maximum absolute deviation and relative deviation are 0.2% and 6.47% respectively. The trends of heat release and adiabatic flame temperature (AFT) are consistent, meanwhile, the trends of LFL are opposite to them. Besides, the trend of the total peak of heat release rate at LFL is consistent with the heat release. H + O2 < = > O + OH mainly reduces the heat release rate, and CH3 + O < = > CH2O + H mainly increases the heat release rate. The sensitivity coefficients of the maximum main chain branching reaction H + O2 < = > O + OH and the main termination reaction H + O2 (+M) < = > HO2 (+M) of the mass burning rate at the LFL are almost the same.