醇/烃燃烧反应机理模型和实验研究

Alcohol/alkane combustion process produces a large number of intermediate products and complicated reaction network. The accuracy and guidance of combustion kinetic has been limited by modern experimental technique and kinetic model predictabilities. Consequently, the TDLAS technique of ‘second harmonic peak versus the fourth harmonic peak’ and continuous spectroscopy detection method was adopted to detect Roaming kinetic of alcohol with shock tube combustion reaction to complete reaction network. Then, focusing on the requirements of kinetic model to predict combustion reactions of different compositions, the Structural class method is introduced into alcohol combustion field by classifiying reaction process into chemical-bond level instead of structural level. After the classification of different reaction processes, functions represent kinetic parameter variation law with molecular structure parameters were presented in view of the Additivity Method、Evans-Polanyi form and shock tube detection technique. With these functions, the influence of molecular structure on reaction processes was apparent. Combined with new kinetic model and experimental technique, it will guide the development of alcohol/alkane combustion technique with excellent accuracy and predictability.

醇/烃混合燃烧反应中间产物众多、反应网络交联复杂。受目前实验技术水平及动力学模型预测能力的影响，醇/烃燃烧动力学模型的准确性及指导性受到限制。拟采用课题组的“二次谐波和四次谐波峰值比值”TDLAS技术及EMCCD光谱连续测量技术，激波实验研究醇类及烷烃Roaming反应动力学常数，完善反应动力学网络。在此基础上针对醇/烃混合燃烧过程需对大量组成物质进行预测的要求，将催化裂解实验研究领域的结构集总方法（Structural class method）推进至化学键层次集总，从而可应用于醇/烃混合燃烧领域。新方法拟在对燃烧反应归类的基础上，结合Evans-Polanyi等方程形式及激波实验测量技术，拟合反应动力学参数随分子结构变化的函数，预测相似类分子结构对各类反应过程的影响从而简化方程，进而预测醇/烃燃烧不同物质组成对反应结果的影响。新的动力学模型及实验技术可有效指导醇/烃燃烧过程预测。

针对燃烧过程存在争议的动力学参数较多，点火延迟方法无法诊断的问题。搭建了激波管-EMCCDOH自由基光谱拍摄平台，首次采用EMCCD连续拍摄了着火过程中的CH*和C2*自由基随时间演变光谱图；构建了以反应物随产物变化一阶导数变化规律为特征，结合自由基演变光谱测量结果的诊断反应动力学参数的一阶求导方法。建立了光谱测量反应自由基演化及烷烃燃烧过程光谱参数诊断的新方法，初步完善了醇/烃反应机理。此外，本项目的分子-结构集总矩阵模型在Curran对燃烧过程的30种物质归类的基础上，拟合了反应动力学常数k随分子结构变化函数方程，将参与30类反应的物质进行矩阵表征，构建了结构导向SR反应动力学模型。相较传统集总方法及常微分方程组求解方法，简化了计算过程，提高了模型对燃烧现象的可预测性。