高瓦斯煤层综掘工作面风流-粉尘两相流动特性

Gas-solid two-phase flow at high-gassy fully mechanized within high gassy coal seam

  • 摘要: 为解决压入式通风条件下高瓦斯煤层综掘工作面粉尘质量浓度高的问题,以山西潞安集团漳村煤矿2601综掘工作面为研究对象,基于气固两相流理论,通过编程计算综掘工作面气载粉尘运移过程,研究了综掘工作面气固两相流动特性,结果表明:在压入式风筒出口与综掘工作面之间存在一个“负压区”,其影响范围随风筒出口风速增大而增大,而中心压力随风速增大而减小。该负压区导致沿综掘工作面回风侧煤壁运移的部分粉尘流分别在掘进机上方涡流、后方回流的携带作用下,从掘进机右侧和后部流经掘进机司机周边,往风筒出口方向运移,导致司机右侧、后部以及进风侧距综掘工作面2.5 m区域的粉尘浓度较高。当风筒出口风速低于17 m/s时,回流粉尘环绕掘进机形成平均质量浓度为300 mg/m3的粉尘带;当风速高于17 m/s时,粉尘带平均质量浓度急剧下降,回流粉尘在进风侧距综掘工作面2.5 m的区域积聚,形成平均质量浓度高于300 mg/m3的粉尘团。因此,应在高瓦斯综掘工作面掘进机的回风侧设置粉尘拦截装置,截断粉尘的扩散路径。同时,需在掘进机的后部设置覆盖工作面断面的除尘装置,对沿回风侧运移的粉尘进行二次拦截,阻挡掘进机后方粉尘回流,提高综掘工作面的能见度。

     

    Abstract: To solve the problem of high dust concentration around the heading face area at a high gassy fully mecha- nized heading face under forced ventilation conditions,the 2601 high-gassy fully mechanized heading face at Zhangcun Coal Mine of Lu’ An Group was taken as the research case. Based on the theory of gas-solid two-phase flow and through programming,the dust carried by air migration process at the fully mechanized heading face was calculated, and the gas-solid two-phase flow law in the heading area at the fully mechanized face was investigated. The results show that there is a negative pressure zone between the outlet of the ventilation cylinder and the heading face,whose influence range increases with the wind velocity of the outlet of the cylinder. With the increased negative pressure zone,the center pressure decreases as the wind velocity increases. Due to the pressure difference in the negative pres- sure zone,part of the dust flow moving along the opposite side of the air cylinder flows under the vortex above the road header and the backflow of the road header,and flows through the road header from the right and rear of the road header. Then the dust gather away from the heading face 2. 5 m in the inlet side,resulting in a higher dust concentra- tion at the right and rear of the driver and away from the heading face 2. 5 m in the inlet side. When the wind velocity at the exit of the air cylinder is less than 17 m / s,the return dust forms a dust belt with an average quality concentra- tion being 300 mg / m3 around the road header,when the wind speed is greater than 17 m / s,the average concentration of the dust belt drops drastically,and the return dust is at the outlet of the air cylinder. It was accumulated to form a dust cloud having a quality concentration of exceeding 300 mg / m3 . Therefore,a dust intercepting device should be in- stalled on the return airflow side of the roadway of high gassy fully mechanized heading face to prevent the dust from moving along the return airflow side to the rear of the working face. Also,a dust removal device covering the cross sec- tion of the working face should be arranged at the rear of the road header to intercept the dust moving along the return airflow side,block the dust backflow behind the road header,and improve the visibility of the heading face.

     

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