【作者】 刘明亮；

【导师】 张超林；

【作者基本信息】 中国矿业大学 ， 安全工程（专业学位）， 2025， 硕士

【摘要】 煤炭资源在我国能源安全保障中发挥基础性作用,近些年来,虽然煤矿的安全生产形式稳步转好,但煤与瓦斯突出事故时有发生。煤与瓦斯突出的本质是煤岩体在高应力与瓦斯压力耦合作用下发生失稳破坏,并伴随煤-瓦斯两相流的高速运移与能量释放过程。近年来,随着开采深度向深部延伸,突出灾害的突发性、隐蔽性和致灾范围显著增强,两相流运移过程的动态传播规律及其致灾效应已成为重点研究方向。基于此,本文通过自主研发的煤与瓦斯突出物理模拟试验系统,开展了CO₂、N₂、He三种不同吸附性气体条件下的突出试验,分析了突出过程中煤层气压、温度参数演化规律及突出两相流的运移规律和致灾效应,结合Fluent软件建立了煤与瓦斯突出两相流模型,模拟了不同条件下的运移动态,并通过下峪口煤矿工程实例验证了模型的适用性。本文的主要结论如下:（1）突出过程中煤层气压呈现快速下降、缓慢释放和稳定三阶段,距突出口越近气压下降速度越快;煤层温度变化经历快速下降、回升和缓慢下降过程。巷道内冲击波超压演化分为初始、衰减、波动和结束阶段,超压峰值及波速随传播距离递减;温度呈现两段式变化,初期骤降后缓慢回升,降温幅度与突出口距离负相关。煤粉运移呈现悬浮流、栓流等多形态,速度在16.20～23.70 m/s间波动,煤粉破碎率随突出距离的增加呈现波动变化,在第一节巷道中的煤粉破碎率最高。（2）气体吸附性对煤与瓦斯突出时煤层的参数演化具有显著影响,气压演化上,随着气体吸附性的降低,煤层气压下降速度增加,He试验组煤层气体压力降至大气压耗时210ms,远短于CO₂试验组,且距突出口越远,气压下降速度越慢;温度演化上,随着气体吸附性的降低,温度下降波谷值降低,从CO₂试验组中的0.21℃降至He试验组中的0.17℃。（3）吸附性差异进一步影响两相流运移特征,CO₂试验组因吸附量高、解吸膨胀做功强,形成更高的冲击波超压峰值且到达峰值的时间最短,在1.5m处,其冲击波超压曲线在突出发生后8 ms时达到峰值25.49 k Pa,随气体吸附性降低,冲击波超压峰值减小、达到峰值时间增加,超压曲线趋于平稳的时间缩短且整体波动更平稳;CO₂高吸附性使突出能量持续释放,煤粉获的更高的初速度并维持栓流形态,而He不吸附,突出依赖游离气体能量,煤粉初速度低,能量耗散快,形成沙丘流与分层流。（4）致灾效应方面,CO₂的强吸附性使得煤体膨胀使得突出煤粉总质量与相对强度达到最大值,分别为6.350 kg、31.75%,且突出煤尘在集尘袋内富集;而He组不吸附于煤层,煤粉破碎率最低且主要沉积于巷道中部,相对突出强度仅为7.27%。（5）基于欧拉多相流模型并依据物理模拟试验系统尺寸构建几何模型,对煤与瓦斯突出两相流进行模拟。模拟结果与试验数据对比,整体趋势一致,验证了Fluent软件模拟的可行性。通过建立真实尺寸的煤矿掘进和回采过程巷道模型对煤与瓦斯突出过程进行模拟,结果表明,掘进时,煤粉运移呈初期分层、后期扩散特征,冲击波速度远高于煤粉,冲击波在运移190 m后仍能对人造成重度伤害;回采时,煤粉在冲击气流下向巷道断面两侧扩散成“梯形”,冲击波初期峰值高达80.24 k Pa,远超人体伤害阈值,且冲击波经巷道拐角时压力集中效应显著,压力会发生陡升。该论文有图42幅,表9个,参考文献93篇更多还原

【Abstract】 Coal resources play a fundamental role in ensuring China’s energy security.In recent years,although the safety production situation in coal mines has steadily improved,coal and gas outburst accidents still occur occasionally.The essence of coal and gas outburst is the instability and failure of coal and rock mass under the coupling action of high stress and gas pressure,accompanied by the high-speed migration and energy release process of coal-gas two-phase flow.In recent years,with the extension of mining depth to the deep,the suddenness,concealment and disaster-causing range of outburst disasters have been significantly enhanced.The dynamic propagation law of two-phase flow migration process and its disaster-causing effect have become the key research direction.In this thesis,through the self-developed coal and gas outburst physical simulation test system,the outburst tests under three different adsorption gas conditions of CO₂,N₂and He were carried out.The evolution law of coalbed methane pressure and temperature parameters in the process of outburst and the migration law and disaster-causing effect of outburst two-phase flow were analyzed.Combined with Fluent software,the two-phase flow model of coal and gas outburst was established,and the migration dynamics under different conditions were simulated.The applicability of the model was verified by the engineering example of Xiayukou Coal Mine.The main conclusions of this thesis are as follows:（1）The coal seam gas pressure during the outburst can be divided into three stages:rapid decline,slow release,and stabilization.The closer to the outburst orifice,the faster the gas pressure drops.The temperature change in the coal seam undergoes a process of rapid decline,rebound,and slow decrease.The disaster-causing effects of the outburst two-phase flow are mainly reflected in the evolution of shock waves and the migration and fragmentation characteristics of coal powder.The evolution of shock wave overpressure in the roadway is divided into initial,decay,fluctuation,and termination stages.The peak overpressure and wave velocity decrease with the propagation distance.The temperature exhibits a two-stage change:a sharp drop in the early stage followed by a slow rebound,with the temperature drop amplitude negatively correlated with the distance from the outburst orifice.The coal powder migration presents suspended flow,plug flow and other forms,and the velocity fluctuates between 16.20～23.70 m/s.The coal powder breakage rate fluctuates with the increase of the outburst distance,and the coal powder breakage rate in the first section of the roadway is the highest.（2）Gas adsorption has a significant effect on the evolution of coal seam parameters during coal and gas outburst.In terms of gas pressure evolution,with the decrease of gas adsorption,the pressure drop rate of coalbed methane increases.The gas pressure of coal seam in He test group decreases to atmospheric pressure in 210ms,which is much shorter than that in CO₂test group.The farther away from the outburst port,the slower the pressure drop rate.In terms of temperature evolution,with the decrease of gas adsorption,the trough value of temperature drop decreases from 0.21°C in the CO₂test group to 0.17°C in the He test group.（3）The difference of adsorption further affects the migration characteristics of two-phase flow.The CO₂test group has a higher peak value of shock wave overpressure and the shortest time to reach the peak value due to its high adsorption capacity and strong desorption expansion.At 1.5 m,the shock wave overpressure curve reaches the peak value of 25.49 k Pa at 8 ms after the outburst.With the decrease of gas adsorption,the peak value of shock wave overpressure decreases and the time to reach the peak value increases.The time for the overpressure curve to stabilize is shortened and the overall fluctuation is more stable.The high adsorption of CO₂makes the outburst energy release continuously,the pulverized coal obtains a higher initial velocity and maintains the plug flow pattern,while He does not adsorb and highlights the dependence on free gas energy.The initial velocity of pulverized coal is low,the energy dissipation is fast,and the dune flow and stratified flow are formed.（4）In terms of disaster-causing effect,the strong adsorption of CO₂makes the coal body expand so that the total mass and relative strength of outburst pulverized coal reach the maximum,which are 6.350 kg and 31.75%respectively,and the outburst coal dust is enriched in the dust collection bag.The He group does not adsorb to the coal seam,the pulverized coal crushing rate is the lowest and mainly deposits in the middle of the roadway,and the relative outburst strength is only 7.27%.（5）Based on the Euler multiphase flow model and the geometric model constructed according to the size of the physical simulation test system,the two-phase flow of coal and gas outburst is simulated.The simulation results are compared with the experimental data,and the overall trend is consistent,which verifies the feasibility of Fluent software simulation.The process of coal and gas outburst was simulated by establishing a real-size roadway model of coal mine tunneling and mining process.The results show that during tunneling,the migration of pulverized coal is characterized by initial stratification and later diffusion.The shock wave velocity is much higher than that of pulverized coal,and the shock wave can still cause serious damage to people after 190 m migration.During mining,the pulverized coal diffuses to both sides under the impact airflow to form a trapezoid.The initial peak of the shock wave is as high as 80.24 k Pa,far exceeding the human body damage threshold,and the pressure concentration effect is significant when the shock wave passes through the corner of the roadway,and the pressure will rise sharply.There are 42 figures,9 tables and 93 references in this thesis.更多还原