燃烧中间产物诊断：宽温度范围振动精细电子光谱理论研究

The diagnosis of combustion intermediates is one of the key problems in aircraft engine combustion due to it involves the verification and theoretical description of the critical element reactions in hydrocarbon fuel combustion. In this project, by investigating the influence of temperature on the vibration-rotation state-state transition of combustion intermediates under extreme conditions, we will develop a theoretical method to calculate fine electronic emission spectroscopy of molecular including vibrational effect, and use it to diagnose combustion intermediates with a wide range of temperature. The project is made of the following three parts. 1) Based on the theoretical spectrum calculation code constructed by our group, we will develop an appropriate method including vibronic effect and program it to calculate fine-electronic spectra. 2) Using this method to simulate the emission spectra of combustion intermediates produced by typical hydrocarbon fuels and construct the spectrum database, we can realize the qualitative diagnosis of key element reactions in combustion process, and provide basic database and theoretical basis for the online verification of combustion mechanism. 3) Applying the relationship of the formation and concentration of combustion intermediates changed with time, we will explore the joint measurement method of multi-species spectrum related time domain. This will provide more pervasive means for the construction of detailed mechanism of combustion reaction and diagnosis of intermediate product with a wide range temperature. The implementation of this project will promote the development of combustion mechanism of hydrocarbon fuel and diagnostic method of combustion intermediates with a wide range temperature, and will provide theoretical support for the development of controllable combustion technology of aircraft engine in our country.

燃烧中间产物的诊断是发动机燃烧的核心问题之一，它涉及燃烧关键基元反应过程的诊断和理论描述。本项目通过考虑温度对极端条件下燃烧中间产物振转态-态跃迁的影响，发展计算分子振动精细发射光谱的理论方法，用于宽温度范围燃烧中间产物的诊断。内容包括：1）基于我们发展的光谱计算平台引入温度对体系振转态-态跃迁的影响，发展包含温度效应的振动精细电子光谱理论并程序化；2）利用此方法计算若干典型大分子碳氢燃料重要燃烧中间产物的发射光谱并构建光谱数据库，实现燃烧关键基元反应过程的定性诊断，并为燃烧机理的在线验证提供基础数据和依据；3）利用燃烧过程中间产物的生成和浓度随时间的演变关系，探索时间域关联的多物种光谱联合测量方法，为燃烧反应详细机理的构建和宽温度范围燃烧中间产物的诊断提供更有效的手段。本项目的实施将促进碳氢燃料燃烧反应机理和宽范围燃烧中间产物诊断方法的发展，为我国发动机可控燃烧技术的发展提供理论支撑。

燃料在发动机内燃烧产生高温（~2000K），在高温环境中通过实验手段诊断燃烧反应中间体是一个巨大的挑战。本项目提出发展理论方法计算燃烧中间产物（包括离子、自由基和大分子）的精细发射光谱，用以辅助实验诊断燃烧中间体，为构建正确的复杂燃烧反应详细机理提供理论依据。依据立项时拟定的研究内容，本项目完成的研究内容和重要结果有：（1）实现了发展包含温度效应和非谐效应的复杂体系振动精细电子光谱计算方法并程序化的目标，用于宽温度范围航空燃料燃烧中间产物的光谱诊断；（2）根据燃烧核心机理的详细基元反应列表，详细计算并研究了十余种燃烧核心机理涉及的小分子烷烃（C1-C4）如C2、OH、CH、OOH、HCO等的高温精细电子发射光谱，并结合实验光谱验证了该方法的可靠性，构建了燃烧核心机理中间产物精细电子光谱数据库；（4）模拟了航空燃料几种典型成分如正十四烷、正十烷、正辛烷、甲基环己烷和甲苯等燃烧产生的中等尺寸中间体如C4H5O(2-甲酰烯丙基)，C4H8O(2,2-二甲基氧基醚)，C5H10O(2,2,3-三甲基环氧乙烷)，C7H7(苄基)等在各种温度下的精细发射光谱并建立了光谱数据库，为燃烧机理的在线验证提供基础数据和依据；（5）探索了时间域关联的多物种光谱联合测量方法。本项目的实施促进了碳氢燃料燃烧反应机理和宽范围燃烧中间产物诊断理论方法的发展，为我国发动机可控燃烧技术的发展提供了理论支撑。