褐煤煤尘爆炸火焰传播特性及燃烧热分解机理研究

煤尘爆炸是矿井安全开采的主要危险源之一。以褐煤煤尘为研究对象，探究煤尘粒径对煤尘火焰传播过程的影响。用高速摄影装置记录火焰的传播过程，进而分析不同粒径下煤尘爆炸火焰传播的高度和速度。为进一步分析煤尘燃烧过程中的化学反应机理，借助反应分子动力学方法对煤分子燃烧中的初始热分解过程进行了模拟。研究结果表明:爆炸火焰传播高度呈先增加、后稳定的趋势，传播速度呈先增大、后减小的趋势；随着煤尘粒径的减小，火焰传播高度和传播速度均呈增大的趋势；当煤尘粒径为10.5 μm时，火焰传播高度和传播速度的峰值分别为623 mm和4.3 m/s；煤尘热分解主要产物为H₂、H₂O、CO₂和CH₂O，这些产物进一步与氧气的结合会促进煤尘燃烧和火焰传播过程，使得整个体系燃速加快。为煤尘热分解和燃烧提供了较为充分的数据基础。

Study on Flame Propagation Characteristics and Combustion Pyrolysis Mechanism of Lignite Dust Explosion

Coal dust explosion is one of the main hazard sources for safe mining in mines. Taking lignite dust as the research object to explore the effect of dust particle size on the coal dust flame propagation. The flame propagation was recorded by a high-speed camera, and the height and velocity of flame propagation in coal dust explosion under different particle sizes were analyzed. To further analyze the chemical reaction mechanism during the combustion of coal dust, the initial pyrolysis process of coal molecules in combustion was simulated through reactive molecular dynamics. Results show that propagation height of flame increases first and then stabilizes, and propagation velocity increasesfirst and then decreases. With the decrease of the particle size of coal dust, the flame propagation height and propagation velocity both show an increasing trend. When the particle size is 10.5 μm, the flame propagation height peak and propagation velocity peak are 623 mm and 4.3 m/s, respectively. The main products of coal dust pyrolysis are H₂, H₂O, CO₂, and CH₂O, and the further combination of these products with oxygen will promote the combustion and flame propagation of coal dust, so that the combustion rate of the whole system is accelerated. It provids a sufficient data support for coal dust pyrolysis and combustion.