Abstract A detailed experimental work is conducted to address the response of premixed syngas-air (H2/CO = 50%/50%) explosion with the effect of equivalence ratio and ignition location. The equivalence ratio, Φ, ranges from 0.8 to 3.0, and three different ignition locations, i.e., left closed end (Ig-1), central duct (Ig-2), and right open end (Ig-3), are considered. Results show that the flame oscillates more violently as the ignition location is set close to the open end. But for a given ignition location, the flame undergoes a similar shape change as the equivalence ratio increases. The pressure dynamics suggest that the pressure waves do a little on the flame propagation as the flame is ignited at Ig-1. But when the flame is ignited at Ig-2 and Ig-3, both the flame tip speed and overpressure oscillate and coincide well with each other, and the pressure waves play an important role in the flame oscillation. What’s more, the parameters, including flame propagation time (t), the maximum flame propagation speed (νMax), and the maximum overpressure (PMax), are obtained. The results indicate that the equivalence ratio and the ignition location are coupled to affect the premixed syngas-air explosion, and the extremum, i.e., minimum t, maximum νMax and PMax, are attained at Φ = 1.4 for Ig-1, at Φ = 1.6 for Ig-2, and at Φ = 1.8 for Ig-3. Finally, the results suggest that the flame ignited at Ig-3 is less destructive, because it has the longest flame propagation time, but the smallest νMax and PMax.

中文翻译：

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当量比和点火位置对半开管道内预混合成气-空气爆炸的影响

摘要 针对当量比和点火位置影响下预混合成气-空气（H2/CO = 50%/50%）爆炸的响应进行了详细的实验工作。当量比 Φ 的范围为 0.8 到 3.0，并考虑了三个不同的点火位置，即左封闭端 (Ig-1)、中央管道 (Ig-2) 和右开口端 (Ig-3)。结果表明，当点火位置靠近开口端时，火焰振荡更加剧烈。但是对于给定的点火位置，随着当量比的增加，火焰会经历类似的形状变化。压力动力学表明，当火焰以 Ig-1 点燃时，压力波对火焰传播有一点影响。但是当火焰在 Ig-2 和 Ig-3 处点燃时，火焰尖端速度和超压振荡并相互吻合，压力波在火焰振荡中起重要作用。此外，还获得了火焰传播时间（t）、最大火焰传播速度（νMax）和最大超压（PMax）等参数。结果表明当量比和点火位置耦合影响预混合成气-空气爆炸，极值，即最小 t、最大 νMax 和 PMax，对于 Ig-1，在 Φ = 1.4 时达到，在 Φ = Ig-2 为 1.6，Ig-3 为 Φ = 1.8。最后，结果表明在 Ig-3 处点燃的火焰破坏性较小，因为它的火焰传播时间最长，但 νMax 和 PMax 最小。和最大超压 (PMax)，得到。结果表明当量比和点火位置耦合影响预混合成气-空气爆炸，极值，即最小 t、最大 νMax 和 PMax，对于 Ig-1，在 Φ = 1.4 时达到，在 Φ = Ig-2 为 1.6，Ig-3 为 Φ = 1.8。最后，结果表明在 Ig-3 处点燃的火焰破坏性较小，因为它的火焰传播时间最长，但 νMax 和 PMax 最小。和最大超压 (PMax)，得到。结果表明当量比和点火位置耦合影响预混合成气-空气爆炸，极值，即最小 t、最大 νMax 和 PMax，对于 Ig-1，在 Φ = 1.4 时达到，在 Φ = Ig-2 为 1.6，Ig-3 为 Φ = 1.8。最后，结果表明在 Ig-3 处点燃的火焰破坏性较小，因为它的火焰传播时间最长，但 νMax 和 PMax 最小。