煤炭在我国能源结构中依然是占有重要地位的基础能源，在推动煤炭清洁高效利用的同时，可再生能源的消纳入网对燃煤机组的灵活性也提出了更高要求。具有高温、瞬态、多相、多组分等复杂特性的煤粉燃烧过程成为制约燃煤机组快速响应负荷变动和稳定运行的关键因素。在此背景下，本文开展复杂气氛条件下煤粉着火和焦炭燃烧特性研究，旨在为燃煤电站运行参数优化、实施灵活调峰、控制污染物排放提供理论基础支撑。首先，基于实验室规模的平面扩散火焰燃烧器，开展了常规工况下环境温度和组分中氧气浓度对煤粉颗粒燃烧行为的影响研究。通过引入先进的平面激光诱导荧光光谱（PLIF）诊断技术，对不同温度、氧气浓度工况下的煤粉颗粒着火延迟时间以及着火模式进行表征。通过耦合煤粉化学渗透热解（CPD）模型以及气相化学反应机理建立瞬态单颗粒煤粉着火模型，对煤粉颗粒的着火模式进行了定量化数值表征以及预测。借助于计算流体力学软件，探讨了颗粒间距对煤粉着火行为的影响。此外，在实验室发展了适用于焦炭燃烧体系的RGB颗粒表面测温方法，并成功测量了焦炭燃烧表面温度随环境温度和氧气浓度的变化情况。其次，研究了富氧工况下较高浓度二氧化碳对煤粉颗粒着火以及焦炭燃烧行为的影响。采用可见光光谱诊断技术，揭示了高浓度二氧化碳气氛下煤粉颗粒着火行为的变化规律。基于瞬态单颗粒煤粉着火模型，分析了二氧化碳不同物理化学性质对非均相和均相着火分别作用效果，获得了高浓度二氧化碳气氛下煤粉颗粒着火模式的转变以及其对最终着火延迟时间的影响规律。同时，借助于RGB测温技术，测量并比较了常规和富氧工况下焦炭颗粒燃烧表面温度。进而，本文关注了气氛中较高浓度水蒸气对煤粉颗粒着火行为不可忽略的影响，分别探究了原煤中水分、环境中的蒸气含量、不同的稀释剂（N2/CO2）以及燃料类型对煤粉颗粒着火行为的影响。基于瞬态单颗粒煤粉着火模型，对水蒸气的物理化学性质对煤粉颗粒着火行为的影响效果进行了定量化敏感性分析。最后，基于实验室新型管状旋流燃烧器，探究了湍流流场对煤粉颗粒着火延迟时间以及着火模式的影响。基于瞬态单颗粒着火模型，分别详细讨论了湍流的传热和传质效应对煤粉颗粒着火行为的影响，揭示了湍流对煤粉颗粒着火模式转变的影响规律。此外，测量并比较了湍流和层流流场中焦炭颗粒燃烧表面温度。

Coal still plays an important role in China’s energy structure transformation. In the pursuit of clean and efficient utilization of coal, the rapid growth of renewable energy in the power grid requires more flexibility for coal-fired units. The pulverized coal combustion process with transient conditions, the multiphase, multicomponent, high temperature as well as other complex characteristics have become a key factor in restricting the rapid response and stable operation of coal-fired units. Therefore, in order to optimize the combustion conditions inside the furnace, it is necessary to have a deeper understanding of the combustion characteristics of pulverized coal particles under the more complex or extrem conditions. In this context, studies on the combustion characteristics of pulverized coal particles in complex ambience was carried out in order to provide theoretical basis for the optimization of operation parameters of coal-fired power plants, the implementation of flexible peak regulation and the control of pollutant emissions.First, based on the bench-scale flat-flame Hencken burner, the influence of ambient temperature and oxygen fraction on the combustion behavior of pulverized coal particles under conventional conditions was investigated. By introducing advanced Laser-Induced Fluorescence (LIF) spectrum, the ignition delay time and ignition mode of pulverized coal particles under the conditions with different temperature and oxygen fraction were characterized. A transient model for single particle ignition was established by coupling the chemical percolation devolatilization (CPD) model and the gas-phase reaction mechanism. In addition, RGB pyrometry was used for particle surface temperature measurement in the char combustion system. The variation of char surface temperature with ambient temperature and oxygen fraction has been successfully measured.Secondly, the influence of carbon dioxide on the ignition of pulverized coal particles and the combustion behavior of char was explored. The ignition behavior of pulverized coal particles at high carbon dioxide concentration was studied by using visible light spectrum diagnostic technology. Based on the transient single particle ignition model, the effects of different physicochemical properties of carbon dioxide on heterogeneous and homogeneous ignition were analyzed. The transition of ignition mode under the conditions with high carbon dioxide concentration and its effect on the overall ignition delay time were further discussed. At the same time, with the help of RGB pyrometry, the surface temperature of char particles under air- and oxy-combustion conditions was measured and compared.Thirdly, the effect of steam in the ambience on the ignition behavior of pulverized coal particles was also discussed. The effects of water content in raw coal, steam content in the ambience, diluents (N2/CO2) and fuel type on ignition behavior of pulverized coal particles were investigated. Based on the transient ignition model, the sensitivity analysis of the physicochemical properties of steam on the ignition behavior of pulverized coal particles was carried out. The influence of steam on the char surface temperature was also quantitatively characterized by RGB pyrometry.Finally, based on the newly-designed tubular swirl burner, the influence of turbulent flow field on ignition delay time and ignition mode of pulverized coal particles was investigated. Furthermore, by virtue of the single particle ignition model, the effects of enhanced heat and mass transfer in turbulence on the ignition behavior of pulverized coal particles were discussed in detail, and the mechanism of turbulence effect on the ignition mode is revealed. In addition, the surface temperature of char particles in turbulent and laminar flow fields was measured and compared.