煤与瓦斯突出过程中含瓦斯煤体粉化作用机理及气固两相流特性研究

The mechanism of coal and gas outburst is the foundation of hazard prevention and have been paid widely attention to by researchers at home and abroad.The start and development process of coal and gas outburst can be concluded:instability conditions,the development of instability to the deep part , the pulverization of instability coal and it's continuous thrown process.The researchers at home and abroad always paid the attention to the first two part,thus paid little attention to the last process and the last process is lack of experiment evidences.In order to solve the problems,This project combine the experimental method and theoretical analysis method to study the last part from the following four aspect:the Pulverization mechanism of coal containing gas ,the pore damage process during pulverization and the reconstruction of the pore,critical desorption character of the pulverized coal, gas-solid two phase flow character during the thrown process.The target of the project is to analysis the pulverization mechanism,the desorption character and the character of gas-solid two phase flow from a point of quantitative view by combining the existing outburst case , establish an model that can describe the pulverization of the coal containing gas, obtain the pore damage law during the pulverization, explain the desorption character during the pulverization from a micro aspect, establish a mathmatical model that can describe the coal-gas two phase flow, finally perfect and develop the outburst mechanism.

煤与瓦斯突出（简称突出）机理是突出灾害防治的基础，受到国内外学者的广泛关注。突出的发动和发展过程可归纳为突出发生的失稳条件、失稳过程连续向煤体深部发展和失稳煤体的粉化、解吸与连续抛出。国内外学者的研究多集中在前两个方面，而对后一个问题研究相对较少且缺乏实验支撑。针对上述现状本项目采用实验研究和理论分析相结合的方法，开展突出过程中含瓦斯煤体的粉化作用、煤体粉化过程中孔隙损伤演化与重构、临界解吸动力学和气固两相流实验和理论研究；结合现有突出案例，定量分析突出过程中煤体的粉化作用、瓦斯解吸动力学和气固两相流特征；建立描述突出过程中含瓦斯煤体粉化作用模型，获得突出煤体粉化对孔隙损伤的演化特征，从微观上解释突出煤体粉化过程中的临界解吸动力学机制，建立描述突出过程中粉化煤体与瓦斯气固两相流数学模型，进一步完善和发展突出机理。

煤与瓦斯突出是煤矿生产过程中遇到的一种极其复杂的瓦斯动力现象，此过程通常伴随有强烈的煤体粉化现象，并形成粉化—快速解吸—继续粉化—进一步快速解吸的正反馈机制，推动突出在巷道内的发展。对突出粉煤-瓦斯流形成机制、运动特征以及煤体粉化在推动突出发展中所起作用开展相关研究，对于丰富和完善突出机理，指导矿井的防突工作具有重要意义。本项目以岩石力学、表面物理化学和两相流体动力学理论为指导，采用理论分析、实验测试和数值模拟相结合的研究手段，通过对煤样粉化前后的基础物性参数、孔隙结构和瓦斯吸附/解吸性能开展精细定量化表征，获得了粉化作用对煤样孔隙结构的损伤特征并构建了粉煤初始瓦斯解吸动力学模型。另外，利用数值模拟和相似模拟实验对突出发展过程中含瓦斯煤体粉化机制以及突出粉煤-瓦斯两相流在巷道中的运动特征开展相关研究，并对含瓦斯煤体粉化与快速解吸在推动突出发展中的作用进行了分析，主要结论如下：. 1）粉化前后，煤的基础成分构成（水分、灰分、挥发分、固定碳等）并无显著改变，但是其孔隙结构却发生明显变化。2）建立了煤孔内瓦斯运移微观模型，得出孔隙损伤对煤孔内瓦斯平衡量无影响，但会加剧煤孔内瓦斯运移速度，使损伤前后运移平衡时间均缩短。3）采用自主研发的试验装置对突出粉煤-瓦斯两相流的结构、形成机制和运动特征开展研究，结果表明突出粉煤和突出瓦斯气流间复杂的气固耦合作用导致粉煤-瓦斯流的流型、冲击波超压、运动速度、突出煤质量分布及分选粉化特征均受到突出压力和突出煤样粒度构成（模拟构造应力在突出发生前对煤体的破碎作用）的影响。4）采用DEM-CFD模拟对突出煤体破碎粉化特点进行研究，发现突出发展过程中巷道内部存在两种碰撞粉化形式，分别是高频低速的颗粒间碰撞和低频高速的颗粒-壁面间碰撞。上述两种碰撞作用都会导致煤体的粉化破碎，前者的粉碎产物以大粒径煤颗粒为主，后者以小粒径煤粉为主。