Abstract This study examines the suppression effectiveness of fluorinated species CHF3 and C2HF5 on the premixed hydrogen-air explosions experimentally and numerically. The results demonstrate that as for stoichiometric and rich hydrogen-air mixtures, both CHF3 and C2HF5 can effectively reduce thermal expansion ratio and increase flame thickness, and then reduce the influence of hydrodynamic instability on the flame acceleration. Laminar burning velocity, the maximum of explosion pressure, the maximum rate of pressure rise and the absolute value of pressure impulse all decrease with increasing suppressant concentration at various equivalent ratios. The maximum of explosion pressures for stoichiometric flames is decreased by 11.54 % with 2 % CHF3 added, and decreased rapidly by 40.39 % with 2 % C2HF5 added. The hydrogen-rich mixtures cannot be ignited when C2HF5 content reaches 10 %. Numerical simulations have confirmed that both CHF3 and C2HF5 can effectively reduce the concentration of active radicals with the decrease order of H > OH > O. C2HF5 is more effective in suppressing explosions than CHF3 by converting more H atoms to HF formation through the elementary reactions CHF2 + H CHF + HF, CF2:O + H CF:O + HF, and CF2 + H = CF + HF.

中文翻译：

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氢氟碳化合物抑制氢气-空气爆炸

摘要 本研究通过实验和数值研究了含氟物质 CHF3 和 C2HF5 对预混氢-空气爆炸的抑制效果。结果表明，对于化学计量和富氢-空气混合物，CHF3和C2HF5均能有效降低热膨胀比和增加火焰厚度，进而降低流体动力不稳定性对火焰加速的影响。在各种当量比下，层流燃烧速度、最大爆炸压力、最大压力上升率和压力脉冲绝对值都随着抑制剂浓度的增加而减小。化学计量火焰的最大爆炸压力在添加 2% CHF3 时降低了 11.54%，在添加 2% C2HF5 时迅速降低了 40.39%。当 C2HF5 含量达到 10% 时，无法点燃富氢混合物。数值模拟证实，CHF3和C2HF5都可以有效降低活性自由基的浓度，递减顺序为H>OH>O。C2HF5比CHF3更有效地抑制爆炸，通过基元反应CHF2将更多的H原子转化为HF形成+ H CHF + HF、CF2:O + H CF:O + HF 和 CF2 + H = CF + HF。