Effects of Carbon Dioxide on Laminar Burning Speed and Flame Instability of Methane/Air and Propane/Air Mixtures: A Literature Review

This work reviews the impact of carbon dioxide (CO2) on laminar burning speed and stability of the flame for methane (CH4) and propane (C3H8) combustion with air. Mixtures of CH4 and CO2, also known as biogas, are considered as low-cost alternative fuels. Biogas is widely used in various industrial and residential applications. Mixtures of C3H8 and CO2 are considered as alternative refrigerants with low global warming potential and low flammability. Laminar burning speeds were reported using different experimental methods. Laminar burning speeds have also been numerically calculated by one-dimensional steady code using three chemical kinetic mechanisms. Results depict a decrease in equilibrium flame temperature and laminar burning speed of both CH4/air and C3H8/air mixtures with the existence of CO2 in those mixtures. The maximum laminar burning speeds of neat CH4 and C3H8 are observed to be in the vicinity of an equivalence ratio of 1.1; however, as the percentage of CO(2 )increases, the maximum laminar burning speeds shift toward stoichiometric mixtures. Carbon dioxide also increases flame thickness and suppresses flame instability by the combination of thermal-diffusive and hydrodynamic effects.