Experimental measurement and theoretical prediction for lower flammability limits of ternary hydrocarbon mixtures

The present work experimentally investigated the lower flammability limits of methane-ethylene-propane-air mixtures at ambient temperature and pressure in a 20 L confined chamber. Moreover, a calculated flame temperature (CFT) modeling for predicting the lower flammability limit of multicomponent mixed combustible gas was proposed based on the law of conservation of energy. The results indicated that the relative error of Le Chatelier's law is 2.88% in the prediction of the lower flammability limit of the tested multicomponent mixed combustible medium. Also, the relative error of CFT modeling is only 1.47%, which is reduced by 48.96% and can significantly improve the prediction accuracy of the lower flammability limit of multicomponent mixtures. Furthermore, using the premixed laminar flame speed reactor, the USC 2.0 mechanism was employed to obtain the behavior of ternary hydrocarbon mixtures near the flammability limits. The sensitivity analysis showed that competition between the chain branching reaction R1 (H + O-2 double left right arrow O + OH) and the chain termination reaction R12 (H + CH3(+M) double left right arrow CH4(+M)) was crucial in determining the lower flammable limit.