为充分认识煤与瓦斯突出冲击气流的形成机理及其传播特征，基于气-固耦合作用下的煤与瓦斯突出物理模拟试验结果，结合气体动力学理论，建立冲击气流的形成及其运移模型，并应用于煤与瓦斯突出冲击气流数值模拟分析。结果表明：煤层瓦斯压力和应力下降过程中皆存在阶段性平稳或回升现象，说明能量的释放是分阶段完成的；煤层应力的变化主要集中在卸压区、应力集中区和过渡区，其中，最大主应力的下降量和下降百分比皆高于最小主应力；当煤层瓦斯压力为2.0 MPa时，巷道内冲击气流速度可超过300 m/s，煤粉流速度受气体曳力带动可达70 m/s；冲击气流速度远大于煤粉流速度，存在气流先行煤粉滞后的现象，由此将煤与瓦斯突出过程划分为单相气流阶段和煤-瓦斯两相流阶段；巷道断面冲击力呈现出不均匀的分布特征，其部分区域出现了冲击力陡增现象；随距离的增加，强冲击力有从断面中心向外部扩展的趋势；冲击气流的流动状态与煤层瓦斯压力、突出孔洞形貌特征有直接关联；冲击气流呈射流状，在射流中会周期性地出现膨胀波区和压缩波区，同时，射流截面会出现周期性的先扩大后缩小现象，从而导致射流边界上下起伏呈波纹状；在冲击气流运移过程中通过其速度演化可划分出高速射流区、平稳运移区和回流区，回流区内存在旋涡；冲击气流受膨胀-压缩波系的影响分别会在巷道内形成楔形真空区和锥形压缩区，其静压分别处于负压状态和正压状态。

In order to fully understand the formation mechanism and propagation characteristics of coal and gas outburst impact airflow, based on the outburst test results under gas-solid coupling, combined with the theory of gas dynamics, the formation and migration model of outburst impact airflow is established in this study.It is further verified by numerical simulation. The results show that the outburst holes extend up to the top of the coal seam and produce layered cracks, and the development of layered cracks is directional. During the process of coal seam gas pressure and in situ stress drop,there is staged stability or recovery, indicating that the release of energy is completed in stages.The changes in coal seam stress are mainly concentrated in the stress relaxation zone, stress concentration zone and transition zone.Among them, the decreasing amplitude of the maximum principal stress is larger than that of the minimum principal stress. When the coal seam gas pressure is 2.0 MPa, the impact airflow velocity in the roadway can exceed 300 m/s, and the pulverized coal flow velocity driven by gas drag can reach 70 m/s. The impact airflow velocity is much larger than the pulverized coal flow velocity, and there is a phenomenon that the airflow is advanced and the pulverized coal lags behind. Therefore, the whole process is divided into a single phase airflow stage and a coal gas two-phase flow stage. The impact force on the section of the roadway shows uneven characteristics, and the impact force has increased sharply in some areas. As the distance increases, the strong impact force tends to expand from the center of the section to the outside. The flow state of impact airflow is directly related to coal seam gas pressure and outburst pore morphology. The impact airflow is jetlike, and the expansion wave zone and compression wave zone will appear periodically in the jet. At the same time, the jet cross section will periodically expand first and then shrink, causing the jet boundary to fluctuate up and down and be corrugated.During the migration process of impact airflow, the high speed jet zone, the smooth migration zone, and the recirculation zone can be divided according to its velocity law. There are vortices in the recirculation zone. The impact airflow is affected by the expansion wave and the compression wave, respectively, forming a wedge shaped vacuum zone and a cone shaped compression zone in the roadway.Its static pressure is in a negative pressure state and a positive pressure state respectively.

1 试验

   1.1 试验设备

   1.2 试验煤样

   1.3 试验方案

   1.4 试验步骤

2 试验结果及分析

   2.1 煤层瓦斯压力演化规律

   2.2 煤层地应力演化规律

   2.3 煤-瓦斯两相流运动特征

   2.4 冲击力演化规律

3 冲击气流形成及其运移理论分析

   3.1 冲击气流形成过程中气流参数分析

   3.2 冲击气流形成模型

   3.3 膨胀波和压缩波的形成

   3.4 冲击气流在巷道内的运移

4 冲击气流形成及运移的数值模拟

   4.1 几何模型及边界条件

   4.2 冲击气流速度演变

   4.3 冲击气流静压演变

5 结论