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Influence of spark duration on deflagration characteristics of methane-air mixtures



Deflagration behavior data of methane/air mixtures for sparks are essential for a detailed quantitative assessment. This article presents the deflagration data of methane/air mixtures for three spark durations: 6.5 μs, 16.1 μs, and 40.6 μs at standard conditions of pressure and temperature. All the presented data were obtained from the experiments conducted in two explosion vessels: the cylindrical one of 5 L volume, and the spherical one of 20 L volume. For the given ignition energy 56 mJ, the maximum deflagration overpressure, the maximum deflagration temperature, the maximum rate of deflagration pressure rise, and the maximum rate of deflagration temperature rise in the 5 L vessel are approximately constant, as the spark durations increases from 6.5 to 40.6 μs. The same conclusion was obtained for the 20 L vessel. Under the same ignition energy of 56 mJ, the deflagration overpressure of methane/air mixture in the 20 L vessel is approximately equal to those in the 5 L vessel, but the deflagration temperature near the wall of 20 L vessel is significantly lower than those near the wall of 5 L vessel. © 2011 American Institute of Chemical Engineers Process Saf Prog, 2011