Burning velocities, quenching, and stability data on nonturbulent flames of methane and propane with oxygen and nitrogen

Critical boundary velocity gradients for flash-backand blow-off, the quenching distances in tubes and between plane parallel plates are presented for the methane-oxygen-nitrogen system. In addition, Lewis and von Elbe's theory of ignition, quenching and stabilization of flames has been further tested on propane flames. For this purpose, burning velocities, flame stability, and quenching data were determined for propane-oxygen-nitrogen mixtures. A new method of determining the burning velocities of Bunsen-burner flames is given, based on the flow of gas through a given surface of the flame cone defined by a frustum of the cone. Comparisons were made of experimental and theoretical values of critical flash-back gradients, flame-quenching distances between plates and in tubes for mixtures of propane and air. The agreement was found to be satisfactory, except for flash-back in very rich mixtures, where the difference between experiment and calculation is, however, only about 6- to 8-fold.