无机固化泡沫流固态下防控高温煤岩裂隙机理研究

Mine fire is one of the main disasters in coal mine. The coal spontaneous combustion induced by the air leakage form coal and rock fracture accounts for more than 90% of the total mine fire. Solidified foam is a new development direction of mine fire prevention materials. It is urgent to investigate the preventing and controlling mechanism of seepage blocking, three dimensional coverage, cooling and heat insulation and continuous consolidation for the high temperature coal and rock fracture. The project will investigate the two chemical processes include the dynamic drainage of foam liquid film and hydration condensation of grain skeleton by chemical thermodynamic analysis and microscopic characterization. The internal thermal stability mechanism of foam fluid under the high temperature environment will be revealed. The fluid thermal conductivity model will be established by the hemispherical steady state method, based on which, the cooling and heat transfer law in the process of the fracture seepage will be revealed using the large eddy simulation. The flow mathematical model of foam fluid in the horizontal single fracture channel will be established and inversed. Considering the gravity and reverse migration of heat gas flow in the fracture channel, the time and temperature-varying diffusion model of foam fluid in the longitudinal, sloping and high fracture will be proposed. The bonding characteristics of interface of foam with coal and rock in fluid and solidified state will be explored. The impact mechanical and energy absorption characteristics of solidified foam under dynamic loading will be investigated. At last, the mechanism and plugging the air leakage and resistance to the mine pressure disturbance by the consolidation of foam with coal and rock fracture will be indicated. The research results can provide theoretical support and scientific basis for coal spontaneous combustion control by foam materials with transformation from fluid state to solidified state .

矿井火灾是煤矿主要灾害之一，其中由于煤岩裂隙漏风导致的煤自燃火灾事故占矿井火灾总数的90%以上。固化泡沫作为矿用防灭火材料发展的一个新方向，亟需开展其流固态下对高温煤岩裂隙渗流封堵、立体覆盖、降温隔热、持续固结等防控作用机理研究。本项目采用化学热动力分析和微观表征研究受热情况下泡沫液膜排液和颗粒骨架水化凝结过程，揭示高温环境对泡沫流体热稳定性影响的内在机制。基于半球面稳态法建立泡沫流体导热模型，运用大涡模拟揭示其在高温煤岩裂隙渗流过程中的降温传热规律。构建并反演水平单裂隙通道内泡沫流体流动数学模型，考虑重力和裂隙内热气流逆向运移阻滞作用，提出纵向倾斜高位裂隙中泡沫流体的时变温变扩散模型。探究其流固态下与煤岩体界面的粘结特性，研究动载荷作用下固化泡沫冲击力学及吸能特性，揭示泡沫固结煤岩裂隙抗矿压扰动持续堵漏风机理。研究成果可为流固态转变的浆泡体系材料高效防治煤自燃火灾提供理论支持和科学依据。

矿井火灾是煤矿主要灾害之一，其中由于煤岩裂隙漏风导致的煤自燃火灾事故占矿井火灾总数的90%以上。无机固化泡沫其流体状态下能够向高处堆积，覆盖包裹高温煤体进行降温，凝结固化后泡沫孔隙率高（闭孔），堵漏隔氧、隔热、阻断高温火源区域蔓延，具有一定的抗压强度，有效减少煤岩固结体二次裂隙发育。但是作为一个流固态转变的浆泡体系，针对煤炭自燃防治，特别是高温松散煤岩体覆盖降温、裂隙持续堵漏风过程中还存在一些亟需解决的问题，如泡沫流体的受热稳定性、裂隙渗流及降温传热特性、裂隙固结抗扰动性能等，其相应的作用机理研究还比较薄弱。.本项目基于颗粒稳定泡沫微观表征、颗粒的润湿、颗粒的水化反应、孔壁固化等几个过程的分析，揭示了泡沫液膜化学热动力排液和颗粒骨架水化凝结过程的协同作用机制；实验室搭建试验平台分析了泡沫流体的热稳定性及隔热特性，揭示了温度对液膜稳定动态平衡方程关键参数的影响机制，并建立了含液膜导热、泡孔气体导热、对流和孔壁辐射传热的降温隔热模型；基于半球型煤堆自燃泡沫流体压注降温实验，得到了高温煤岩裂隙通道内泡沫流体流动过程中的降温传热规律，并分析得出了泡沫流体增强粘结煤岩体界面的物理作用机理；实验测定了泡沫流体粘度随时变及温变耦合特性，基于粘变时变的宾汉流体模型，推导了泡沫流体水平单裂隙通道内流动数学模型，得到了泡沫流体水平裂隙通道内部渗流扩散形态及规律，并进行了参数敏感性分析；考虑重力和高温煤岩裂隙通道中热气流逆向扩散运移压差影响，推导了裂隙面不同方向上倾斜裂隙中泡沫流体的扩散模型，并采用数值模拟进行了求解；基于动载荷条件下其工程应力压溃试验，得出了无机固化泡沫在不同冲击能量及不同填充密度下的变形模式，揭示了泡沫填充前后吸能特性差异的内在机制，研究成果为浆泡材料流固态下高效防治煤炭自燃及煤田火灾提供了理论指导。