Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA.
J Phys Chem A. 2010 Aug 19;114(32):8286-301. doi: 10.1021/jp1047002.
A new technique is proposed that uses theoretical methods to systematically improve the performance of chemical kinetic mechanisms. Using a screening method, the chemical reaction steps that most strongly influence a given kinetic observable are identified. The associated rate coefficients are then improved by high-level quantum chemistry and transition-state-theory calculations, which leads to new values for the coefficients and smaller uncertainty ranges. This updating process is continued as new reactions emerge as the most important steps in the target observable. The screening process employed is a global sensitivity analysis that involves Monte Carlo sampling of the full N-dimensional uncertainty space of rate coefficients, where N is the number of reaction steps. The method is applied to the methanol combustion mechanism of Li et al. (Int. J. Chem. Kinet. 2007, 39, 109.). It was found that the CH(3)OH + HO(2) and CH(3)OH + O(2) reactions were the most important steps in setting the ignition delay time, and the rate coefficients for these reactions were updated. The ignition time is significantly changed for a broad range of high-concentration methanol/oxygen mixtures in the updated mechanism.
提出了一种新的技术，该技术使用理论方法系统地改进化学动力学机制的性能。使用筛选方法，确定对给定动力学观测值影响最大的化学反应步骤。然后，通过高级量子化学和过渡态理论计算来改进相关的速率系数，从而得到系数的新值和更小的不确定范围。随着新反应成为目标观测值中最重要的步骤，更新过程会继续进行。所采用的筛选过程是一种全局敏感性分析，涉及到对速率系数的完整 N 维不确定性空间进行蒙特卡罗采样，其中 N 是反应步骤的数量。该方法应用于 Li 等人的甲醇燃烧机理。（Int。J.Chem。Kinet。2007，39，109。）。结果发现，CH（3）OH + HO（2）和 CH（3）OH + O（2）反应是确定点火延迟时间的最重要步骤，并且更新了这些反应的速率系数。在更新的机理中，对于大范围的高浓度甲醇/氧气混合物，点火时间发生了显著变化。
