Research On Law Of Dust Emission Transport In Coal Mine Haulage Roadway And Atomization Dust-settling Technology

Mine dust pollution does great harm to workers who work underground, which is the biggest problem of occupational diseases in the coal mining industry. Transportation roadway mainly consist of belt roadway for coal and auxiliary transport roadway for the material transport and pedestrian. The harm of dust in transport lane is different from working face, so we must carry on targeted research on it. Based on field observation and Experimental Research, the three-dimensional numerical simulation was carried out Using COMSOL Multiphysics 5 to study the effect of airflow factors, vehicle operation, the belt running process on dust; Based on the program of heat and mass transfer equations during the droplet evaporation process, simulation test on the evaporation process were carried out using Matlab14.0, to explore and derive calculation equation of the survival time of droplet, in order to support improving the efficiency of reducing dust for spray; According to the theoretical analysis, field test, numerical simulation, experiment and simulation experiment, spray dust suppression system process was optimizated and investigated its effect in field application. The main research results are as follows:(1) We developed the calculation of Influence theory about effects of airflow temperature, humidity, pressure on the wind power density, dynamic viscosity, and Study on the effect of its moisture content on the density and Particle size. The temperature reduces, humidity increases and pressure reduces resulting in dynamic viscosity of air reduces. The increase of water content will lead to the increase of particle density and particle size.(2)Three-dimensional value simulations researches on the effect of tunnel wind raising dust and wind power transport on tunnel flow velocity, vehicle and the running belt, dust particle size change are conducted. The results show that with the wind velocity increasing, the raising dust intensity is increscent, in a certain range, dust concentration is reduced but pollution range is wider. After a long distance, the dust concentration is increased with the wind velocity increasing; when vehicle runs before the wind,25-30m away from the front, bimodal distribution of dust concentration appears. When vehicle runs behind the wind,25-35m away from the back, unmoral distribution appears. Peak value of contrary wind is far outweigh one of tailwind, with the vehicle velocity increasing, raising dust intensity and concentration is bigger; The belt amplitude, velocity and shake frequency are increased, raising dust intensity and concentration is bigger.(3)Experiments study on the atomization nozzle and dust efficiency calculation are conducted. The results show that on the condition of air pressure 0.11-0.65 MPa, water pressure 0.45-2.55 MPa, ALR 0.02-0.11 and water flow 500-700 kg/h of PZT(ψ1.2mm) nozzle, droplet velocity is 70-220 m/s, particle size is 20-80 μm, dust removal efficiency reaches 90%.(4) Using Matlabl4.0, based on the heat and mass transfer of droplet evaporation in the process of governing equations, procedures is written to simulat and analysis the evaporation process. There are 6 main factors that affecting the droplet evaporation process are droplet radius, relative velocity, initial droplet initial temperature and airflow, temperature, humidity, air pressure etc. The other 5 factors are the key factors to influence the survival time of the particle except the initial temperature of the droplet. With the increase of initial droplet radius, relative humidity, air pressure, prolong the survival time of droplet. As the increase of relative velocity of droplets and air, the ambient temperature and the initial temperature of droplet, the survival time is reduced. Through the uniform with the factor analysis dimension reduction, for the first time, deducing the calculation equation of droplets containing 5 key attributes and environmental attributes the survival time of the particle, which is compared with the experimental results show high precision formula.(5)The effect of automatic spray suppression system is used in the field to investigate. According to the results of numerical simulation and experiment, the method of roadway dust monitoring and automatic spray dust control dust is put forward, automatic spray dust suppression system is built,field application and efficiency of reducing dust is carried out. The results show that the reducing dust efficiency of the automatic spray dust suppression system can reach more than 86%.