Synergetic effects in flames of mixtures of methane and carbon monoxide with air

Numerical simulation has shown that replacing a part of methane by carbon monoxide in a rich mixture while maintaining the equivalence ratio leads to a decrease in the superadiabatic temperature effect due to the competition of chemical reactions. This has been explained by a decrease in the $\mathrm{H}$ content in the combustible mixture and a decrease in the superequilibrium concentration of water in combustion products. Using the tracer numerical simulation method and a comparative analysis of the rates of consumption of $\mathrm{CH}_4$ and $\mathrm{CO}$, it has been established that the consumption of both fuels in the $\mathrm{CH}_4/\mathrm{CO}$/air flame is a competitive reaction path and $\mathrm{CO}$ monoxide does not act as an inert component in the low-temperature region of the front (contrary to the statements of a number of authors). Furthermore, the rate of consumption of $\mathrm{CH}_4$ is much higher than that of $\mathrm{CO}$ due to the larger number of paths of consumption of $\mathrm{CH}_4$ and their higher rates. The main contribution to the increase in the concentration of $\mathrm{H}$ atoms in the flame when replacing a methane-air mixture with a CH${}$/CO/air mixture is due to the same reactions that increase the heat release rate: $\mathrm{O}+\mathrm{CH}_3=\mathrm{H}+\mathrm{CH}_2\mathrm{O}$ и $\mathrm{CO}+\mathrm{OH}=\mathrm{CO}_2+\mathrm{H}$. The results obtained and their comparison with literature data lead to the conclusion that the increase in the heat release rate and, hence, flame propagation rate should be greater in rich mixtures, since there the thermophysical effect is higher.