对异十六烷详细机理的简化研究

Study on Detailed Mechanism Reduction of Iso-cetane

异十六烷作为一种异构烷烃,常用作构建模型燃料模拟汽车发动机的实际燃油来分析发动机的燃烧或排放特性。利用包含误差传播的直接关系图法(DRGEP)对异十六烷反应机理进行初步简化;利用生成/消耗速率分析法(ROP)对反应机理进行二次简化,分析各组分反应速率并删除次要组分及其参与的次要反应,并通过粒子群算法优化敏感反应的参数来减小ROP简化后的模拟结果偏差;采用敏感性分析法(SA)对反应机理进一步简化,分析对三种反应器的重要反应,并分别以自定义阈值删除目标参数的次要反应或补充重要反应,最终得到83组分299步反应的异十六烷简化机理。结果表明,简化后的机理在描述异十六烷与空气燃烧过程的滞燃期、反应物和产物的组分浓度演变历程以及火焰传播速度方面具有和详细机理相当的计算精度。

As a kind of iso-paraffin, iso-cetane is often used as a component in the fuel models to simulate and analyze the combustion or emission characteristics of the actual fuels used in automobile engines. The reaction mechanism of iso-cetane was preliminarily reduced by using the method of directed relation graph with error propagation （DRGEP） and was secondarily reduced by rate of production （ROP） and consumption analysis. According to the analysis results of ROP, the secondary species and reactions involved were deleted, and to minimize tile calculation deviation after tile ROP reduction, tile particle swarm optimization algorithm was used to optimize the parameters in the sensitive reaction steps. The sensitivity analysis （SA） was used to further reduce the mechanism, the important reactions of three reactors were analyzed and the thresholds were determined for deleting the secondary reactions or adding the important ones. Finally, the reduced iso-cetane mechanism with 299 steps and 83 species was obtained. The verification shows that the calculation results by using the reduced mechanism agree well with the experimental data in terms of the ignition delay time, the species concentration during the combustion process and the laminar flame speed.