Abstract:

To study the effect of the multiple concentrations and ignition locations on the characteristics of the premixed hydrogen-air deflagration, an experimental study is conducted in an elongated transparent square cross-section duct closed at one end and open at the opposite end. The results show that hydrogen concentration and ignition position exerted a great impact on the evolution of flame front structures. The reaction under each equivalence ratio proceeded most rapidly when the mixture was ignited at 100 mm from the closed end. The ignition position has a greater influence on flame development in very lean or rich fuel. The hydrogen concentration and ignition position simultaneously affected the pressure waveform. The overpressure waveform under different equivalence ratios presents complex changes when the ignition occurred in the left and right parts of the duct respectively, with the 300 mm from the closed end as the boundary of ignition position. The overpressure peak has a strong dependence on hydrogen concentration, and the effect of concentration on the overpressure peak is much greater than that of ignition location. The maximum overpressure peak was obtained in Φ = 1.25 at all ignition positions. the maximum overpressure corresponds to the ignition position which is depending on the equivalence ratio.

Key words: hydrogen, concentration, ignition position, deflagration, pressure

摘要：

开展了氢气-空气预混气在透明方管内的爆燃实验研究，分析在一端开口一端封闭的狭长空间内，浓度和点火位置对氢气-空气预混气爆燃特性的影响。实验结果表明：氢气浓度和点火位置对火焰锋面结构以及发展有重要影响；各当量比条件下，均在距封闭端100 mm位置点火时反应最为迅速；在极贫燃或极富燃条件下，点火位置对火焰发展影响更大。氢气浓度与点火位置共同作用于压力波形，以距封闭端300 mm点火位置为界，分别在管道前后两段点火时，不同当量比条件下超压波形呈现复杂变化。超压峰值对氢气浓度具有极强依赖性，并且浓度对爆燃超压的影响程度远大于点火位置；在各点火位置下，均在Φ = 1.25时获得最大超压；最大超压对应的点火位置取决于当量比。

关键词: 氢气, 浓度, 点火位置, 爆燃, 压力