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 near-cryogenic 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 five different chemical mechanisms. First, for all fuels, the laminar burning velocity evolution as a function of the equivalence ratio followed the same trend at 295 K and 240 K. Regardless of the equivalence ratio and mixture composition, the laminar burning velocity decreased by 22 to 44% for hydrogen, methane, ethane, ethylene, and propane flames when the temperature was decreased from 295 K to 240 K. Second, for stoichiometric conditions, the laminar burning velocity decreased by about 50% for all fuels, when the temperature was decreased by 100 K, from 295 to 195 K. These experimental results were in excellent agreement with laminar burning velocities calculated by a power law of the ratio of unburned gas temperature to ambient temperature, with exponent values from the literature, obtained for temperatures above the ambient. All five chemical mechanisms provided a very good agreement, within or near experimental uncertainties, for most of the fuels and conditions investigated, even at low temperatures. 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 for conditions below ambient temperatures.