| As the primary energy of the main raw material, coal plays an important role in China’s economic development and social progress, but mine accidents still occur from time to time, not only caused huge economic losses, but also have a great threat to the safety of human life. In all coal accidents, coal gas accidents have accounted for a large proportion, especially the work surface corner gas gauge problem. Therefore, how to deal with the coal gas problems is related to the important factors affecting whether safety production can be done in coal mine. High pumping Lane achieved some results in dealing with the corner gas gauge problems in some high gas coal mines, which is being used in more and more different coal mines.Whether the high pumping Lane is useful to extract gas has a great relationship with the arrangement of layers.This paper will use numerical simulation to analyze the distribution and transport conditions of the gas in goaf and determine the reasonable arrangement position of high pumping Lane. The paper detailedly describes the goaf gas sources, influencing factors and gives the amount of gas emission related formulas; analyze goaf cross three zones (natural accumulation areas, load-affected zone and compaction stable region) and vertically (the basic nature of the fractured zone and caving zone) and give the solution method hulking districts coefficient; give calculation methods of the goaf porous medium model and its main parameters, and analyzes the mined-out area gas rose float, diffusion and aggregation of the basic characteristics and the resulting related causes; analyze the base layer bit selects high roof roadway drainage pumping gas and layout of the basic mechanism of high pumping Lane and establish the continuity equation, momentum conservation equation, energy conservation equation and control basic equations differential equations, numerical simulation provides a theoretical and mathematical foundations.This paper combines the actual data of Zhangji Mine1111working face to establish the basic physical model of goaf, set parameters and boundary conditions. By making us of simulation software Fluent, we do the following tasks:(1) When the wind speed is2m/s, we simulate the overall gas distribution and then intercept vertically Om (face floor),4m (face plate),16m (in caving band),30m (in fractured band), horizontally10m,20m,60m,120m,250m, the300m, the tilt direction from the return air tunnel4m,30m,90m,130m,170m.It is observed that the vertical direction from the bottom to the fractured face tape ministry, gas concentration tends to gradually increase the horizontal distance from the face near to far, from small to large gas distribution after stabilize the tilt direction from the inlet to the return airway Lane, gas concentration increases. At the same time, the corner gas gauge is serious, which reached12.1%, not conducive to safe work. By increasing the air inlet velocity to3.5m/s, the gas distribution is basically consistent with the regular law. By observing the main work surface, it is easily found the gas concentration in upper corner also seriously overweight. It shows only by increasing the amount of wind can not effectively govern the gas gauge problem.(2)When distance is from the return air lane22m, select the vertical height of26m,34m,42m,50m and58m, then use Fluent to simulate the gas distribution in goaf, the gas distribution is basically consistent with the regular law. Natural gas accumulation zone and affected zone load a certain concentration is diluted, but has little effect on the stability of compaction zone, however, large differences in corner work surface angle and high pumping Lane gas concentration, high pumping selected vertical height of34m Lane when the minimum Upper Corner Gas concentration, while the highest concentration of high pumping gas Lane. When determining the vertical height of34m, the tilt direction of the mountains from the selected return airway22m,30m,38m,46m,54m simulate these points, draw the most appropriate30m distance, this time on the Upper Corner Gas concentration reaches0.7%while the high pumping Lane gas highest concentration of30%is reasonable.When in a fixed tilt direction from the return airway22m, select the vertical height of26m,34m,42m, set by the actual data mining and Zhang compared the actual face of high pumping Lane arranged in vertical height from the bottom face32m, tilt direction from the return airway27m, and there is a certain bias in the simulated data. However, the actual average monthly drained gas concentration was28.5%, on the Upper Corner Gas average concentration of about0.75%, consistent with the high pumping Lane analog layout determined; it is believed that the horizon is more appropriate. |
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