On the controlling mechanism of the lower turning point in the negative temperature coefficient regime

In this study, a comprehensive computational investigation is conducted to observe the negative temperature coefficient (NTC) behavior of the explosion limit of propane explored with detailed chemical kinetics, to find on the controlling mechanism of the lower turning point in the negative temperature coefficient region. The results show that the global behavior of the lower turning point exhibits distinct thermodynamic and chemical kinetic characteristics under different equivalence ratios from those thermodynamic and chemical kinetic characteristics under different inert gas ratios. Further chemical analyses demonstrate that the lower turning point is determined by the competition between chain termination reactions and chain branching/propagation reactions in the low-temperature reactions. Therefore, the ratio of the hydroxyl radical (OH) production rate to the total production rate of the alkyl radical (R) is constructed, which captures the turnover state of the lower turning point in the NTC regime.

Automated summary

Through detailed chemical kinetics calculations, a comprehensive computational investigation is conducted to observe the negative temperature coefficient (NTC) behavior of the explosion limit of propane. The study reveals distinct thermodynamic and chemical kinetic characteristics of the lower turning point under different conditions. The results also show that the competition between chain termination reactions and chain branching/propagation reactions determines the lower turning point in the negative temperature coefficient region.