| Construction of sinking and driving engineering, especially drilling、blasting、loading and unloading, during which could produce amount of dust and poisonous&dangerous gas(such as CO、H2S、NOx), however, whether working face is fine would directly influence company’s development ratio、economical benefits and production safety, therefore, working face must be ventilated topically and uninterruptedly. In allusion to those characteristics of long distance excavation roadway such as far distance to ventilate, duct leakage large, mine dust and fume filled the posterior tunnel and all hard to relief, mines usually use The hybrid local ventilation mode to solve the problem of environmental pollution of working face.Pressure pump hybrid ventilation, which is compressed-in type ventilation system is arranged ahead, pressing fresh air into working face in order to enhance air speed of working face and speed up fume exhausting; drawer-type ventilation system is arranged behind, pulling dirty air out of working place, what matters of whether the effect of ventilating dust is ok is the distribution of fan stack and the ratio of pressing volume with pulling volume.So, what should be of great significance to enhance the ventilation efficiency of dust, create fine working condition, reduce the dust hazard and insure employees’ safety and healthiness, and improve the efficiency of company’s production, is grasping the law of migration and diffusion of dust which is in excavation roadway in the hybrid wind field, and researching the distribution mode of pressing and pulling fan stack.This article combines the physical truth of blasting and ventilation dust of Qinglong mountain fluorite ore of Shilei Mining co.,LTD, Quan’an, bases on CFD, the gas-solid two-phase flow theory, utilize discrete phase model(DPM) of the software of FLUENT, runs numerical simulation to blasting dust’ diffusion and density distribution during pressure pump hybrid ventilation in excavation roadway, vividly shows the relationship of blasting dust’s change of concentration in any place with time during compound ventilation; by changing the space between ram mouth and head end, the ratio of pressing volume with pulling volume, the height of fan stack hanging, and comparing the effect of dust discharging after 15 minutes under different condition, obtain reasonable parameters of compound ventilation of pressing ahead and pulling behind.Research results declare: when it uses compound ventilation mode of pressing ahead and pulling behind for driving working face, airflow field of roadway could divide into five characteristic regions, which are joint jetting region between the tunnel mouth and jet turning point, eddy zone from jet turning point to working face, eddy zone, eddy zone produced when efflux entrainment reflux, common active region by pressing air and pulling air between pumping ram suction to pressing ram export.Too close or too far from pressure pump ram to head-on surface is to the disadvantage of ventilation and dust discharging, there exists the best arrangement for pressure pump ram of hybrid ventilation, the closer tuyere is from this best place, the better ventilated effect will be, conversely the worse effect.For the roadway model of this mine, Sectional area is about 4.3m2. And when distance between pressing ram export and head-on surface is L压=8m~10m,distance between pumping ram suction and head-on surface is L抽=30m~35m, when the ratio of pressing volume with pulling volume is 1:1.4, effect of dust discharging will be better. |
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