碳氢可燃物碳黑生成特性及普适数值模型的研究

As one of the key factors of fire hazards prevention and risk assessment, soot is not only determined by fuel type, but also affected by various environmental factors. On the one hand, the sooting propensity of solid combustibles was mainly characterized by macro-parameters due to the complexity of pyrolysis and combustion, without considering the mutual effect between pyrolysis in solid phase and combustion in gas phase. On the other hand, as an important factor of soot production, the conclusions about the effect of ambient temperature and humidity on soot production under different experimental conditions are inconsistent. The cause may be that the effect of the fuel molecular structure and flame flow structure was not taken in to consideration. In this study, the simultaneous thermal analyzer will be coupled with a gas burner, and the pyrolysis process in solid phase and combustion process in gas phase will be analysed synchronously to explore the influence mechanism of pyrolysis process on the soot production. Further more, the flame flow structure, flame temperature and soot extinction coefficient of typical gaseous, liquid and solid fueled flame with different size will be surveyed under different ambient temperature and humidity, in order to study coupling effect of the ambient temperature and humidity, and the fuel molecular structure, flame flow structure. On the basis of experiments, an universal soot model will be developed in combination with the concept of smoke point height, which further provides reliable test data and theoretical model support for the fire hazard assessment and smoke control.

碳黑是火灾防治和风险评估中的重要因素之一，燃料的碳黑生成特性不仅与燃料种类有关，也会受到众多环境因素的影响。一方面，由于固体可燃物热解燃烧的复杂性，目前对其碳黑生成特性的研究以宏观参数表征为主，忽略了固相热解和气相燃烧之间的相互影响；另一方面，环境温湿度作为影响碳黑生成的重要因素，不同实验条件下得出的结论存在较大差异，没有考察燃料分子结构和火焰流场结构的影响。本研究拟通过同步热分析仪耦合气体燃烧器，同步分析固体可燃物的固相热解过程和气相燃烧过程，深入探索固相热解过程对碳黑生成的影响机理；通过测量不同温湿度环境下典型气、液、固碳氢可燃物的火焰流场结构、温度特征和烟气消光系数等，深入研究环境温湿度与燃料分子结构和火焰流场结构的耦合效应。在上述实验研究的基础上，结合烟点高度的概念，发展适用于固体可燃物和多燃料火灾场景的普适的通用碳黑模型，为火灾危险评价及烟气防治提供重要的实验依据和理论模型。

碳黑是烟气的主要成分，是火灾风险评估和防治中的重要因素之一。燃料的碳黑生成特性不仅与燃料种类有关，也会受到众多环境因素的影响。一方面，环境温湿度作为影响碳黑生成的重要因素，目前研究中不同实验条件下得出的结论存在一定差异；另一方面，固体燃料由于其热解燃烧过程的复杂性，其碳黑生成特性更为复杂，目前相关研究偏少。本研究基于消光法原理，搭建火焰碳黑测量平台以及反演算法，开展环境湿度对火焰碳黑生成特性开展实验和模拟研究，分析水蒸气含量对碳氢燃料火焰的碳黑浓度的影响机理。同时在该实验平台基础上开展固体可燃物火焰碳黑生成特性的探索研究，发现典型木材的碳黑生成能力存在随燃烧进程逐渐增大的现象。本研究基于燃料的烟点高度特征，结合混合分数燃烧模型，提出一种适用于多燃料燃烧场景的通用碳黑模型，可提高火灾危险评估中烟气预测的准确性，为烟气防治提供重要的实验依据和理论模型。