正癸烷热解的小规模化学动力学机理模型

Small-Scale Chemical Kinetic Mechanism Models for Pyrolysis of n-Decane

正癸烷是目前常用的吸热型燃料的替代组分,但是其热解机理的研究迄今还很少,且现有的少数几个机理由于规模庞大使用不便.本文首先构建了一个包含33种组分和75个基元反应的正癸烷热解动力学机理模型(Mech33);随后,在该机理的基础上进一步通过灵敏度分析得到影响主要热裂解组分生成的速率控制步,并采用局部平衡和稳态假设对Mech33机理简化得到了规模更小的、仅包含22种组分和59步反应动力学机理模型(Mech22).在较宽的温度和压力范围内对流动反应器及激波管中正癸烷热解过程进行了数值模拟,并与实验数据进行了对比,结果表明,Mech33和Mech22两个动力学机理模型都能够很好地描述正癸烷热裂解过程,并准确预测主要热裂解产物的浓度分布,为进一步实现化学反应与计算流体力学(CFD)耦合的工程计算提供了有价值的动力学机理模型.

n-Decane is a component of commonly used fuels, but so far studies into its pyrolysis mechanism are rare and the few existing mechanisms are inconvenient to use owing to their large scales. A small-scale chemical kinetic model （Mech33） for describing the process of n-decane pyrolysis containing 33 species and 75 elementary reactions was constructed. Based on partial equilibrium and quasi-steady state assumptions through sensitivity analysis, a smaller kinetic model （Mech22） containing 22 species and 59 reactions was developed from Mech33. Simulations of n-decane pyrolysis using these two models were compared with experimental data from flow reactor and shock tube over a wide range of temperatures and pressures. The results showed that Mech33 and Mech22 could reproduce the process of n-decane pyrolysis well and accurately predict the concentrations profile of main products, and finally provide valuable chemical kinetic models for engineering simulations when coupled with computational fluid dynamics （CFD）.