Numerical Simulation Of Coal Dust Concentration And Removel Of Seven Meters Fully-excavating Working Face

Coal, dust, gas, water, fire and roof disaster is one of the five major disasters in coalmine. Among them, the coal dust disaster is the most serious one. With the rapid development in recent years and the national expend of science and technology, manufacturing, coal mining industry in the development of driving technology make a spurt of progress, the use of mechanical technology and efficient implementation of the high yield of mining coal face amount. The rapid development of these technologies, bring great profits to the coalmine enterprises, at the same time very serious dust harm, which caused permanent physical and psychological harm to the workers.The traditional mining height were between3.5-4.3meters, with China demand on energy grows everyday, especially demand for coal. Coalmine production has been unable to meet the traditionalneeds. In recent years, the original roadway work surface height has been lift to seven meters, referred to as seven meters of large mining height fully mechanized face. Work surface height of lifting, yield improvement at the same time, a number of coal mining has already can’t use dust removal of the original equipment. Because the height of tunnel increases nearly three meters, space is increased, flow of coal dust in the space are influenced by many factors become irregular. This brings great challenge to dust and dust removal equipment.This article base on the working face with large mining height coal processing difficulty, seriously coal dust concentration exceed the standard, dust irregular distribution and blur distribution degree. According to the actual size of coal mining equipment in coal roadway and the roadway in the existing basis, numerical simulation method through calculation, simulation of fully mechanized working face each works the coal dust concentration distribution and fresh air and coal mixture distribution. The simulated step by step and different particle size of coal cutting work surface of shearer drum large mining operations when the dust particle surface in the space, and the simulation analysis of coal dust concentration distribution of large mining height fully mechanized working face with or without the installation of dust equipment by FLUENT software. The simulation in this thesis accords with the actual data, the indicators in roadway, the coal mining face in prevention and treatment plays a pertinent suggestions.The key research contents of this thesis are as follows:(1) In fluid mechanics and multiphase flow (two-phrase flow of gas and solid) theory as the basis, establish mathematical model, analysis of large mining height fully mechanized working face coal dust movement distribution law and its influencing factors.(2) Through the tunnel operation parameters measured the air velocity and the drum cutting coal, establishes the physical model, analysis of fully mechanized working face between the drum and workers of airflow distribution characteristics of work zone and coal dust concentration distribution.(3) According to Venturi jet theory, using air curtain air barrier function, put forward by coal dust drift and theory method of air curtain, was established using the air curtain isolation of dust model.(4) Through the analysis of a variety of air curtain installation scheme, simulation calculation and different parameters, the optimum design selection and installation of air curtain parameters.(5) On the work face cutting coal dust by diameter of particle concentration grading analysis, analysis of working face coal dust: the average diameter of particles are between11μ m～39μ m, respirable dust, which less than6.2μm is accounted for7.2%~21%; the percentage of dust particle size less than35μmincrease at a uniform speed, the percentage of diameter of35%~95μm dust continue to decline.