Study On Gas-liquid Two-phase Flow Ultrasonic Atomization And Dust Suppression Technology In Heading Face

The demand for coal in today's society is still huge.With the development of the times and the advancement of science and technology,coal mining enterprises have continuously increased the degree of underground mechanization,and their investment in coal mine safety has also increased correspondingly.The incidence of coal mine gas explosions,water penetration and other accidents has decreased.It ignores the harm of coal mine dust to coal mine production and the health of miners.Coal mine dust is also one of the main disasters underground.When dust reaches certain conditions,it will cause an explosion.Coal mining companies have also taken corresponding measures.The prevention and treatment of pneumoconiosis is rare,causing a large number of miners to suffer from pneumoconiosis and continue to suffer from the pain.,Especially in fully mechanized tunnels,the pathogenicity is higher.The maximum dust concentration of tunnel excavation during work can reach1000mg/m3.Traditional spray and ventilation have obvious effect on dust reduction.The dust reduction effect of respirable dust is not ideal.The decisive factor for pneumoconiosis is the particle size less than 5?m.Respirable dust.Therefore,this paper uses ultrasonic atomization dust suppression technology and numerical simulation to analyze the dust removal effect,and establish a similar simulation experimental model for experimental verification.The specific conclusions are as follows: The environmental temperature has a greater influence on the water absorption rate of coal dust.Under saturated water mist conditions,the ambient temperature continuously increases from 20°C to 40°C.The water absorption rate of coal with the same degree of deterioration first increases and then decreases.The environment temperature corresponding to the best coal dust water absorption rate is 27.5°C.The average water absorption rate under the saturated water mist environment is higher than that under the relative humidity of 97%,indicating that the saturated water mist environment is indeed good for dust reduction,not only because the particle size of the droplets produced by ultrasonic atomization is close to the fine dust particles.Diameter,easy to condense,but also because of heterogeneous condensation to strengthen the condensation of dust particles and droplets.The simulation results show that when the vertical distance H=1.1m,R=0.2m,v=20m/s,the flow field is relatively concentrated,there is no obvious flow field at the outlet of the dust suction port,the flow field presents a W-shaped movement,and the dust is relatively concentrated.In addition,the transportation time is relatively appropriate,the dust particles are fully in contact with the water mist,and dust and water mist will not accumulate,which further increases the probability of dust and droplets contacting,and the dust concentration fluctuation range is small and the concentration is low.Similar experimental results show that among the factors that affect the dust reduction efficiency of ultrasonic atomization,the particle size of coal powder has the most significant influence on the dust reduction effect.As the particle size of pulverized coal particles becomes smaller,the dust reduction efficiency is improved,especially for improving the dust reduction effect of respirable dust.With the increase of the air intake speed of the dust suction port,the sedimentation efficiency of the ultrasonic atomization dust reduction device for all dust and respirable dust continues to increase.The dust reduction effect of ultrasonic atomization dust reduction device is generally better than that of water mist.The dust reduction effect of the two atomization methods has its advantages and disadvantages in total dust,but the dust reduction efficiency of ultrasonic atomization is significantly higher than that of water mist.Dust down.The research results show the superiority of ultrasonic atomization technology,provide experimental basis for reducing the concentration of total dust and respirable dust,and have positive significance for the formulation of dust prevention measures for tunneling.