正庚烷冷焰-热焰转捩过程的燃烧化学研究

In recent years, due to the occurrence and development of self-sustaining and stable cool flame, the studies focused on cool flame are obtained extensive attentions and more interests. Combustion chemistry characteristics in the transition process from n-heptane cool flame at low temperature to hot flame at high temperature are studied in this project using counter-flow diffusion flame. The key flow and thermal parameters were fine-tuned carefully, and flames were photographed at a high speed. Subsequently the critical conditions and transition time scale of the transition process of cool flame-hot flame can be determined, flame spectrum structure, temperature field and nanostructures of soot particles were analyzed, temperature field and soot particle concentration distribution were rebuilt. Combustion major species and stable intermediates are sampled, on-line identified and quantified near the critical point, meanwhile the chemical dynamics of cool flame and hot flame were simulated at the same critical point. Combustion reaction mechanism of the transition process was established. This study can deepen the understanding of cool flame-hot flame transition phenomenon. It also can provide supports to enhance the cool flame combustion theory and the transition theory of cool flame-hot flame.

近年来，随着可自身维持稳定且持续燃烧（自维持）冷焰的实现与发展，针对冷焰的研究受到了越来越多的关注。本项目基于对冲火焰平台，对正庚烷冷焰低温燃烧向热焰高温燃烧转变的转捩过程开展研究。通过微调节流动、热力等关键参数和捕捉冷焰-热焰转捩过程的动态火焰，确定发生转捩的临界条件以及转捩过程的时间尺度，分析获得转捩过程的火焰光谱结构、温度场变化及烟黑颗粒物的微观结构特征，并对温度场及烟黑颗粒物浓度分布进行重建；在线辨识和定量分析转捩临界点附近可测范围内的燃烧主要产物和稳定中间产物的化学组份，并对转捩临界点附近的冷焰、热焰进行化学动力学模拟，构建转捩过程的燃烧化学反应机理。本研究可深化认识和理解冷焰-热焰转捩现象及其本质，为丰富冷焰燃烧理论及冷焰-热焰的转捩理论提供支持。

本项目基于对冲火焰平台，对正庚烷冷焰低温燃烧向热焰高温燃烧转变的转捩过程开展研究。通过微调节流动、热力等关键参数和采用告诉摄影相机捕捉冷焰-热焰转捩过程的动态火焰，确定发生转捩的临界条件以及转捩过程的时间尺度，分析获得转捩过程的火焰动力学特征，并对温度场进行重建；采用在线辨识和定量分析检测了转捩临界点附近可测范围内的燃烧主要产物和稳定中间产物的化学组份，并对转捩临界点附近的冷焰、热焰进行化学动力学模拟，分析研究了冷焰-热焰转捩过程的燃烧机理。本研究可深化认识和理解冷焰-热焰转捩现象及其本质，为丰富冷焰燃烧理论及冷焰-热焰的转捩理论提供支持。