基于CFD-DPM方法的通风速度对煤尘扩散影响分析

Influence of ventilation velocity on coal dust diffusion based on CFD-DPM method

压入式通风的通风速度直接影响着煤尘颗粒的扩散,从而降低掘进机驾驶员的能见度和掘进机的运行效率。为减少煤尘扩散,基于CFD-DPM方法选取山西长治张村煤矿2601综采工作面作为物理原型,研究不同通风速度下煤矿巷道的气流流动和煤尘扩散行为。模拟结果表明,气流场可分为气流快速和混乱的湍流区、有煤尘回流的回流区以及从掘进工作面到煤矿巷道出口的稳定区。受巷道头阻塞的影响,沿巷道壁面的气流将煤尘颗粒从湍流区带离压力区,进入回流区;由于气流速度的突然下降,煤尘迁移在巷道后面的区域减慢,然后大量的煤尘颗粒被气流带到稳定区域;而煤尘回流造成剩余的煤尘被带到风筒的出口,因此在巷道端头后约5 m的区域,以及风筒附近的区域,煤尘浓度很高。在强夹带作用的影响下,煤尘颗粒被吸引到风筒出口附近,其煤尘浓度随着通风速度的增加而增加,且这种情况发生在通风速度超过17 m/s时。

The ventilation of pressure cylinders directly affects the diffusion of the dust particles,which reduce the visibility of road-header drivers,and also tend to slowdown operating efficiency.Taking the 2601 mechanized working face of a coal mine in Shanxi as an example,CFD-DPM method was adopted to examine the airflow flow and dust diffusion behaviors in roadway under various ventilation velocities.The simulation results show that airflow field could be divided into airflow fast and chaotic disordered area,recirculation area with dust backflow,and stable area from the heading face to the exit of the roadway.The airflow was observed to carry the dust particles along the roadway wall away from the pressure cylinders from the disordered areas into the recirculation areas due to the blocks caused by the road-headers.The dust migration slowed down in the areas behind the road-headers due to the sudden decreases in the airflow velocities.Then,large amount of dust particles were carried by airflow into the stable areas.The remaining dust was carried to the exits of the pressure cylinders as a result of the dust backflow.As a result,areas of approximately 5 m behind of the road-headers,as well as the areas near the pressure cylinders,had high dust concentrations.The dust particles were attracted to the exits of the pressure cylinders due to the strong entrainment effect,and its concentration increased with increasing of the ventilation velocities.However,this only occurred when ventilation velocities exceeded 17 m/s.