Laminar Burning Velocity of Hydrogen, Methane, Ethane, Ethylene, and Propane Flames at Near-Cryogenic Temperatures

The primary objective of this study is to measure the laminar burning velocity of perfectly premixed hydrogen-air, methane-air, ethane-air, ethylene-air, and propane-air flames, at nearcryogenic temperatures and atmospheric pressure. Initial fuel-air mixture temperatures as low as 160 K were investigated. The experimental methodology was validated by comparing the results obtained with those from previous studies available in the literature and with numerical simulations using four different chemical mechanisms. First, for all fuels, the laminar burning velocity as a function of the equivalence ratio followed the same trend at 295 K and 240 K. Regardless of the equivalence ratio, the laminar burning velocity decreased by at least 20% for hydrogen flames, and around 30% for methane, ethane, ethylene, and propane flames when the temperature was decreased from 295 K to 240 K. Second, for stoichiometric conditions, when the temperature of the mixture was decreased, the laminar burning velocity decreased linearly for all fuels with different decay rates. The effect of temperature on the laminar burning velocity was the most pronounced for hydrogen with a rate of 0.89 cm/s/K. The linear decrease rate was 0.18 cm/s/K for methane, 0.16 cm/s/K for ethane, 0.29 cm/s/K for ethylene, and 0.16 cm/s/K for propane flames. All four chemical mechanisms provided a good agreement for hydrogen, methane, and ethane fuels, even at low temperatures. However, for propane and ethylene flames, the best results were obtained with the UCSD and AramcoMech2.0 mechanisms. A reason for this result is proposed. Overall, this study provides valuable information on the laminar burning velocities of various hydrocarbon and hydrogen fuels at near-cryogenic temperatures, which can be useful for the design of cryogenic storage systems and the validation of chemical kinetic models.