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首页> 外文会议>Twenty-Ninth International Symposium on Combustion Hokkaido University >EXTINCTION OF PARTIALLY PREMIXED FLAMES
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EXTINCTION OF PARTIALLY PREMIXED FLAMES

机译：熄灭部分熄灭的火焰

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Experimental and numerical studies on extinction of laminar partially premixed flames are carried out. The studies are performed in the counterflow configuration. A premixed fuel-rich mixture of methane (CH_4), oxygen (O_2), and nitrogen (N_2) is injected from one duct while a fuel-lean mixture of CH_4, O_2, and N_2 is injected from the other duct. The levels of partial premixing are given by the equivalence ratios Φ_r of the fuel-rich mixture and Φ_1 of the fuel-lean mixture. Here Φ = Y_F/(蚘_(O_2), where Y_F and Y_(O_2) are, respectively, the mass fractions of fuel and oxygen at the injection planes (exit of the ducts), and v is the stoichiometric mass ratio of fuel to oxygen. Previous studies have established that the scalar dissipation rate at extinction depends on the stoichiometric mixture fraction, ξ_(st), and the adiabatic temperature, T_(st). To clarify the influence of partial premixing on extinction, studies are carried out at fixed values of ξ_(st) and T_(st). For Φ_r~(-1) = 0, experiments show that the value of the strain rate at extinction, α_q, increases with increasing Φ_1. For Φ_1 = 0, experiments show that the value of the strain rate at extinction, α_q, decreases with increasing Φ_r~(-1). Numerical calculations are carried out using a detailed chemical-kinetic mechanism and an one-step chemical-kinetic mechanism. The values of α_q calculated using the detailed mechanism are found to agree well with experiments. The values of α_q calculated using the one-step mechanism do not agree with experiments. In fact, calculations with the one-step mechanism show the values of α_q to decrease with increasing Φ_1, and increase with increasing Φ_1~(-1). The differences in critical conditions of extinction obtained using the detailed mechanism and the one-step mechanism are attributed to differences in flame structure.
机译：对层状预混火焰的熄灭进行了实验和数值研究。研究是在逆流配置中执行的。从一个导管中注入甲烷（CH_4），氧气（O_2）和氮气（N_2）的预混合的富含燃料的混合物，而从另一导管中注入CH_4，O_2和N_2的贫燃料混合物。部分预混合的水平由富燃料混合物的当量比Φ_r和贫燃料混合物的当量比Φ_1给出。此处Φ= Y_F /（蛔_（O_2），其中Y_F和Y_（O_2）分别是在喷射平面（管道出口）处燃料和氧气的质量分数，而v是燃料的化学计量质量比以前的研究已经确定灭绝时的标量耗散率取决于化学计量的混合分数ξ_（st）和绝热温度T_（st）。为了阐明部分预混对灭绝的影响，我们进行了研究。在固定值ξ_（st）和T_（st）的情况下，当Φ_r〜（-1）= 0时，实验表明消光应变率值α_q随着Φ_1的增加而增加;对于Φ_1= 0时，实验结果表明，消光应变速率α_q随Φ_r〜（-1）的增加而减小，采用详细的化学动力学机理和一步法化学动力学机理进行了数值计算。用详细的机理发现与实验吻合得很好，计算出的α_q值使用单步机制与实验不一致。实际上，通过单步机制进行的计算表明，α_q的值随Φ_1的增加而减小，而随Φ_1〜（-1）的增加而增加。使用详细机理和一步法机理获得的灭绝临界条件的差异归因于火焰结构的差异。

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