Analytical prediction of syngas induction times
Analytical prediction of syngas induction times
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DOI：
10.1016/j.combustflame.2016.11.008
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发表时间：
2017-02
影响因子：
4.4
通讯作者：
P. Boivin;A. L. Sánchez;F. Williams
中科院分区：
文献类型：
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作者：
P. Boivin;A. L. Sánchez;F. Williams
计算表明，在所有可能的条件下的实际利益，包括温度以上和以下的交叉温度，在该温度下的H2+ O2分支和终止步骤的速率是相等的，12个不可逆的基本步骤足以提供准确的值的诱导时间在自燃过程中的燃料组成的混合物的H2，CO，和惰性气体。在高温下，这一时间由自由基池达到稳态所需的时间控制，在这段时间内的热释放可以忽略不计。这个时间很好地近似的时间，它将采取HO2达到稳定状态，如果它的消耗率是由H2O2的形成在所有温度下，因为它是在低温下占主导地位。在交叉温度以下，达到HO2稳态的时间变得比诱导时间短，并且一旦HO2达到稳态，热释放变得不可忽略，导致诱导时间逐渐接近热爆炸的时间，这包括H2O2的有效自催化生产。在这些观察的基础上，这里引入了解析近似，使感应时间在所有条件下都能准确计算。
Computations indicate that, under all possible conditions of practical interest, including temperatures both above and below the crossover temperature at which the rates of the H2+ O2branching and termination steps are equal, twelve irreversible elementary steps suffice to provide accurate values of induction times in autoignition processes of fuels consisting of mixtures of H2, CO, and inerts. At high temperatures, this time is controlled by the time required for the radical pool to reach a steady state, with heat release being negligible during that time. This time is approximated well by the time that it would take for HO2to reach a steady state if its consumption rate were dominated by formation of H2O2at all temperatures, as it is at low temperatures. Below the crossover temperature, the time to reach an HO2steady state becomes shorter than the induction time, and the heat release becomes non-negligible once HO2has reached a steady state, resulting in the induction time progressively approaching that of a thermal explosion, which includes an effectively autocatalytic production of H2O2. On the basis of these observations, analytical approximations are introduced here that enable induction times to be calculated accurately under all conditions.