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为了解单步反应机理的不足及其不同速率表达式之间的差异,分别采用详细和单步化学反应机理数值模拟了甲烷一维层流预混火焰。详细机理预报的火焰速度在整个可燃范围都与实验结果吻合,而单步机理只在贫燃条件下才能给出定量相符的结果,在富燃条件下定性和定量预报结果均不合理。同时,单步机理预报的温度和浓度分布也存在较大偏差,特别是在富燃区。进一步研究表明,用有些常见单步反应速率表达式获得的预报值在整个可燃范围都是不合理的。这些结果对选取反应模型和获得可信预报结果有参考意义。
In order to understand the shortcoming of the single-step reaction mechanism and the difference between different rate expressions, a one-dimensional methane laminar premixed flame was numerically simulated by a detailed and single-step chemical reaction mechanism. The flame velocity predicted by the detailed mechanism coincides with the experimental results over the whole flammability range. However, the single-step mechanism can give quantitative results only under lean-burn conditions, and the qualitative and quantitative prediction results are not reasonable under rich conditions. At the same time, the temperature and the concentration distribution of single-step mechanism forecast also have big deviations, especially in the rich area. Further studies have shown that predictions obtained with some common single-rate reaction rates are not plausible over the entire flammability range. These results have reference meaning for selecting reaction model and obtaining credible forecast results.