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首页> 外文会议>International Seminar on Fire and Explosion Hazards >Extinguishment and Enhancement of Propane Cup-Burner Flames by Halon and Alternative Agents
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Extinguishment and Enhancement of Propane Cup-Burner Flames by Halon and Alternative Agents

机译：哈龙和替代剂的丙烷杯燃烧器火焰的灭火和增强

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Computations of cup-burner flames in normal gravity have been performed using propane as the fuel, in addition to a propane-ethanol-water mixture studied previously, to reveal the combustion inhibition and enhancement by the CF_3Br (halon 1301) and potential alternative fire-extinguishing agents (C_2HF_5, C2HF_3Cl_2, and C3H2F3Br). The time-dependent, two-dimensional numerical code, which includes a detailed kinetic model (up to 241 species and 3918 reactions), diffusive transport, and a gray-gas radiation model, reveals unique two-zone flame structure. For propane, general trends in the structure are similar to those of the fuel mixture. The peak reactivity spot (i.e., reaction kernel) at the flame base stabilizes a trailing flame, which is inclined inwardly by a buoyancy-induced entrainment flow. As the volume fraction of agent in the coflow increases gradually, the premixed-like reaction kernel weakens, thus inducing the flame base detachment from the burner rim and blowoff-type extinguishment eventually. The H_2O in the inner zone, is converted further, primarily in the outer zone, to HF and CF_2O through exothermic reactions most significantly with the C_2HF_5 addition. Despite endothermic decomposition of the agent, exothermic reactions of the inhibitor fragments also contribute to the heat-release rate in the outer zone. Although the rates of formation (and associated heat-release rates) of HF and CF_2O are lower for propane, compared to the fuel mixture, two heat-release-rate peaks in the two-zone flame structure in the trailing flame are comparable for both fuels. A main heat-release step to form CO_2 in the hydrocarbon-O_2 combustion takes place in-between the two zones. The total heat release of the entire flame decreases (inhibiting) for CF_3Br but increases (enhancing) for the halon alternative agents, particularly C_2HF_5 and C_2HF_3Cl_2. Addition of C_2HF_5 results in unusual (non-chain branching) reactions and increases total heat release (combustion
机译：除了先前研究的丙烷 - 乙醇 - 水混合物之外，还使用丙烷作为燃料进行正常重力的杯燃烧器火焰的计算，以揭示CF_3BR（HALON 1301）和潜在的替代火灾的燃烧抑制和增强 - 灭火剂（C_2HF_5，C2HF_3CL_2和C3H2F3BR）。时间相关的二维数值代码，包括详细的动力学模型（最多241种和3918个反应），扩散运输和灰气体辐射模型，揭示了独特的双区火焰结构。对于丙烷，结构中的一般趋势与燃料混合物的一般趋势类似。火焰碱处的峰值反应性点（即反应核）稳定尾部火焰，其通过浮力诱导的夹带流向向内倾斜。随着CoFlow中的试剂的体积分数逐渐增加，预混合的反应核削弱，因此最终从燃烧器边缘和吹气式灭火器诱导火焰基座脱落。内部区域中的H_2O在除了C_2HF_5的加法中，通过放热反应进一步转换为HF和CF_2O，通过放热反应。尽管对药剂的吸热分解，但抑制剂片段的放热反应也有助于外部区域中的热释放速率。虽然与燃料混合物相比，丙烷的形成（和相关的热释放速率）HF和CF_2O的形成率（以及CF_2O的速率较低，但是在尾部火焰中的两个区域火焰结构中的两个热释放速率峰对两者相当燃料。在烃-O_2燃烧中形成CO_2的主要热释放步骤发生在两个区域之间。对于CF_3BR，整个火焰的总热量减少（抑制），但为哈隆替代剂，特别是C_2HF_5和C_2HF_3CL_2增加（增强）。添加C_2HF_5导致异常（非链条支化）反应并增加总热释放（燃烧）

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