An analytical evaluation of flammability limits of gaseous mixtures of combustible-oxidizer-diluent

This paper is aimed at the creation of new methods for the analytical evaluation of flammability limits of ternary gaseous mixtures of combustible-oxidizer-diluent. The physical nature of flammability limits is considered using some peculiarities of the chemical kinetics of combustion of gaseous organic substances in air. New,, features of lower flammability limits and compositions of mixtures near peak points of flammability curves are revealed. These features are the following. Firstly, adiabatic flame temperatures, T-ad,T-co of combustion of gaseous mixtures up to CO and H2O for Mixtures of fuel-air at lower flammability limits and mixtures of fuel-air-diluent at peak points of flammability curves are in rather narrow ranges. Secondly. compositions of ternary gaseoue mixtures of fuel-air-diluent are close to stoichiometric in relation to combustion up to CO and H2O. It was found that such parameters as adiabatic flame temperature, T-ad,T-Co, and equivalence ratio in relation to combustion up to CO and H2O are important for evaluation of flammability limits in ternary gaseous mixtures. New analytical methods for the calculation of flammability limits in mixtures of combustible-oxidizer-diluent are proposed, which have acceptable accuracy for practical applications. (C) 2002 Elsevier Science Ltd. All rights reserved.