不同分子结构含氧燃料掺混正庚烷自着火特性的实验和机理研究

本项目以常规含氧燃料（二甲氧基甲烷、碳酸二甲酯）和新型含氧生物燃料（戊醇、2,5-二甲基呋喃）为研究对象，利用激波管在不同当量比和宽广初始温度压力下（特别是高压、中低温条件）研究不同分子结构含氧燃料对正庚烷着火延迟期和着火极限的影响规律，拟合正庚烷掺混含氧燃料着火延迟期的Arrhenius关系式。利用敏感性分析，生成速率分析和反应流分析探究主导不同含氧燃料着火化学的关键物种和基元反应，验证和优化现有含氧燃料的详细化学反应机理。阐明高压和中低温条件下不同分子结构含氧燃料对正庚烷负温度系数着火行为的影响规律，建立混合燃料碳氧比与总体活化能拐点温度的定量关系式，构建适用于模拟含氧燃料-正庚烷混合燃料燃烧与着火的详细动力学机理和适用于CFD模拟的骨架机理。本研究对发展混合燃料低温着火理论有重要的科学意义，为燃用不同含氧燃料的燃烧设备优化提供指导和可靠的实验支撑，具有重要的工程应用价值。

Experimental and kinetic study on the effects of oxygenated fuel on ignition delay characteristics of n-heptane, especially at low and intermediate temperatures, will be conducted in this project by using shock tube and Chemkin packages. Four representative oxygenated fuels will be blended with n-heptane including the conventional oxygenated fuels (dimethoxymethane, methyl carbonate) and recently interested biofuels (pentanol, 2,5-dimethylfuran).The ignition delay time and auto-ignition limit will be determined under different initial temperature, initial pressure, equivalence ratio and oxygenated fuel addition conditions. An Arrhenius-type correlation will be derived to predict the ignition delay time of oxygenated fuel and n-heptane blends over wide range conditions. The detailed kinetic models of oxygenated fuel will be developed and optimized by sensitivity, rate of production and flow reaction analysis. The objectives are to clarify the effect of oxygenated fuels with different molecular structure on negative temperature coefficient (NTC) behaviors of n-heptane especially at high pressure and intermediate-low temperature conditions, to establish relationships between C/O ratio and the inflection point temperature of activation energy and to propose the detailed kinetic models of oxygenated fuel-heptane blends and skeletal kinetic models suitable for CFD simulation. This research has important scientific significance on developing low temperature ignition theory of oxygenated fuel and n-heptane blends and also provides reliable experimental support for designing and improving the combustion chamber of practical burning equipment with different oxygenated fuels to achieve high efficiency and low pollutant emission.