多孔材料对瓦斯、煤尘复合火焰微观结构及其传播特性影响的研究

The methane and coal dust explosion accidents are the most severe disasters in the coal mines. In recent years, the research of preventing gas explosion and alleviating the damage focuses on the mechanics of blocking explosion propagation and substantially suppressing the shock waves resulting from gas explosions. .A rectangular deflagration test pipe was designed, which has a 100mm×100mm cross-section and is similar in shape to the roadways in coal mines. The experimental platform on hybrid flame fine structure is built up, which includes the high-speed Schlieren photograph system, the high-speed photomicrography combined with laser light, the ion current probe measurement system, super thin thermocouple system and pressure transducer system. .The microscopic structures of hybrid flame impacted by porous materials are disclosured by both high-speed photomicrography (photomicrographs of laser scattering images, high-speed Schlieren photograph, self-luminous images.) and the flame structure parameters (wave pressure, ion current intensity and temperature), which are examined by the flame fine structure experimental platform. The effect rules of hybrid flame propagation and transition mechanism affected by the types，thickness and pore structures of porous materials, the species, density and granularity of coal particle, the equivalence ratio of premixed methane-air are analyzed. Based on multiphase fluid mechanics and combustion theory, combined with experimental results and simulation, the critical conditions to suppress the methane and coal dust hybrid flame spreading are determined and their characterization methods are advanced. The relationship between inhibiting the hybrid flame spread and the characteristics of porous materials is found out. .The researches can improve flame spreading theory of two-phase flow, and provide the useful experimental data and theoretical basis to prevent the methane and coal dust explosion accidents in coal mines.

煤矿井下发生的瓦斯、煤尘爆炸事故是最为严重的煤矿灾害，阻隔爆炸传播过程的机理研究和抑制技术用于瓦斯爆炸防治，是近年来人们研究矿井瓦斯爆炸防治的热点。本研究在可放置多孔材料的密闭燃烧管道内，利用高速显微摄像系统拍摄多孔材料前后的瓦斯、煤尘复合火焰自发光、纹影及激光散射显微图片的同时，结合压力传感器、离子探针和微细热电偶测量技术探测多孔材料前后复合火焰面附近的压力、离子电流和温度分布规律，揭示多孔材料作用下瓦斯、煤尘复合火焰微观结构；分析多孔材料类型、厚度、孔隙结构、煤的种类、浓度、粒度和瓦斯浓度对复合火焰传播及其失稳的影响规律；基于多相流体力学、燃烧学等理论基础，结合实验及模拟结果，确定多孔材料抑制瓦斯、煤尘火焰传播的临界条件和表征方法，寻找出多孔材料特性与抑制复合火焰传播之间的关系。本研究成果不仅能完善两相流火焰传播理论，同时为控制矿井爆炸事故提供坚实的理论基础和可靠的实验数据。

煤矿井下是一个瓦斯和煤尘共存的体系，瓦斯、煤尘爆炸事故是最为严重的煤矿灾害，阻隔爆炸传播过程的机理研究和抑制技术用于瓦斯爆炸防治，是近年来人们研究矿井瓦斯爆炸防治的热点。为了研究多孔材料作用下受限空间内瓦斯火焰形态、超压及火焰传播机制等规律，利用实验研究、数值模拟和理论分析相结合的方法分别研究了多孔材料对空管道内瓦斯火焰传播特性和煤尘在瓦斯爆燃过程中的燃烧特性，得到如下成果：（1）在实验方面，高速摄影技术用来记录瓦斯爆燃过程中的火焰形状变化和火焰前锋位置随时间的变化关系，压力传感器用来测量瞬态超压随时间的变化关系。研究了空管道和置障管道内火焰传播过程中的火焰形状变化、火焰传播速度及升压特性等规律。通过对比分析，揭示了火焰在各工况下的加速机理和层流火焰向湍流转捩的机制。（2）在数值模拟方面，采用大涡模拟对管道内瓦斯火焰传播动力学进行数值模拟，并与实验结果对比，验证数值模拟的有效性，并借此分析火焰形态变化的原因。（3）在理论方面，理论推导了密闭空间内瓦斯火焰总表面积、管道内压力和压力上升速率的关系表达式。揭示了煤尘在瓦斯爆燃过程中的燃烧特性，提出了两步分阶段反应模型来描述煤的氧化热解的吸氧增重和燃烧过程；提出了两步连续反应模型来描述煤的氧化热解过程。（4）研发了用于抑制瓦斯爆炸有机多空材料。揭示了单一孔和二维孔，以及金属丝网、金属泡沫和有机泡沫3种三维多孔材料对瓦斯火焰传播的影响。研究了多孔材料作用下管道内瓦斯火焰传播的失稳机理，确定了多孔材料特性与抑制火焰传播之间的关系。相关研究结果在Journal of Hazardous materials、Energy & Fuel、Combustion theory and Modeling、Journal of Loss Prevention in the Process Industries、Process safety Progress、International Journal of Mining Science and Technology，以及爆炸与冲击、工程热物理学报和采矿与安全工程学报等期刊上，共发表论文19篇，其中SCI刊源期刊7篇，Ei刊源期刊4篇。本研究的开展为防治矿井瓦斯、煤尘爆炸提供坚实的理论基础和可靠的实验数据，也有利于推动气体爆炸这一学科的发展。