模型燃料组分变化对着火延迟NTC特性的影响研究

着火延迟的负温度系数（NTC）现象是长链碳氢燃料低温氧化的标志性特征，是构建模型燃料的重要验证指标，迄今为止国际上尚未对其进行系统化、定量化的研究。本项目针对着火延迟的NTC现象这一燃烧反应动力学的关键特征，利用加热型快速压缩机平台，测量二十二种典型单体碳氢化合物在典型工况下着火延迟的NTC特性，提出了量化着火延迟NTC现象的三项指标（起始温度、持续区间、NTC强度），揭示燃料分子结构的不同引起NTC变化的规律。进一步通过反应机理研究，从动力学角度阐释着火延迟NTC现象的产生机制和差异。基于上述试验和理论研究，系统开展九种组分构成不同的模型燃料自着火试验，深入揭示组分变化对模型燃料NTC特性的影响规律，并从组分和机理角度阐明组分构成与着火延迟NTC现象之间的定性关系。本项目将初步建立碳氢燃料着火延迟NTC特性数据库，完善NTC理论，为模型燃料NTC特性的调控和设计提供基础理论支撑。

The negative-temperature coefficient (NTC) behavior of ignition delay time is an iconic feature of the low-temperature oxidation of long-chain hydrocarbons, and is an important verification index for formulating surrogate fuels. So far, there has been no systematic and quantitative research on it. Aiming at the NTC behavior of ignition delay time, a key characteristic of the combustion reaction kinetics, this project uses a heated rapid compression machine to measure the NTC characteristics of ignition delay time of twenty-two typical hydrocarbons under typical operating conditions, proposes three indicators (initiation temperature, duration, NTC intensity) for quantizing NTC behavior, and reveals the regularity of NTC changes caused by the difference in fuel molecular structures. By further exploring the reaction mechanism, this project explains the generation mechanism and differences of the NTC behavior from a kinetic perspective. Based on the above experimental and theoretical studies, the project systematically tests the autoignition of nine surrogate fuels with different composition, in-depth reveals the influence of composition changes on the NTC characteristics of surrogate fuels, and clarifies the qualitative relationship between NTC behavior and surrogate composition from the perspective of component and mechanism. This project will initially establish a database of NTC characteristics of hydrocarbon ignition delay time, complete the NTC theory, and provide basic theoretical support for the regulation and design of the NTC characteristics of surrogate fuels.