Experimental Research And Engineering Practice On The Combined Control And Dust Reduction Technology Of Water Curtain And Air Curtain In Comprehensive Excavation Face

With the improvement of mechanization level in coal mine excavation,the production of flour dust during excavation work has sharply increased,posing a serious threat to coal mine safety production and the physical and mental health of workers.Water curtain and air curtain are commonly used dust control measures in comprehensive excavation tunnels,but subjective experience is often used in the application process for on-site layout and working condition parameter settings,which is not scientific and reasonable enough.Unreasonable layout and structural parameter design will increase the ventilation resistance of the tunnel,reduce the dust control efficiency of water curtain and air curtain,and lead to poor dust prevention and control effect.In order to give full play to the dust control and fall performance of the two,this thesis takes the water curtain and air curtain as the research objects,carries out the research on the structural parameter optimization of the water curtain and the dust fall performance test,the structural design of the air curtain and the dust control performance research,and puts forward the technical system of combined mining face dust control based on head-on spray,air curtain and water curtain,and has achieved the following research results:Based on the application background of water curtain dust reduction technology in coal mines,the mechanism of water curtain dust reduction was analyzed and explained,and the key structural factors affecting the dust reduction performance of water curtain were determined.Reasonably designing different factor parameter levels,using a self-developed experimental platform,the dust reduction performance and ventilation resistance characteristics of water curtain at different factor levels were studied based on orthogonal experiments.The results show that the smaller the mesh size of the screen,the more favorable the formation of dust trapping water film,and the higher the strength and toughness between the water films.However,it also leads to an increase in ventilation resistance in the tunnel,which is not conducive to the discharge of dust containing airflow;With the increase of the distance between spray and screen,The efficiency of dust settling exhibited a pattern of decreasing initially and then increasing,while the ventilation resistance showed a negative correlation with distance;The inclined state of the screen hinders the formation of dust capture water film,resulting in a decrease in dust reduction efficiency and an increase in ventilation resistance in the tunnel;In addition,with the increase of spray pressure(more than3MPa),the increase of dust reduction efficiency of the water curtain slowed down and the ventilation resistance increased significantly.Finally,according to the test results,it is determined that the optimal working condition parameters for the application of the water curtain are screen mesh diameter 2 * 2mm,full section vertical layout,spray arranged at 1.2m on the wind side of the screen mesh,and spray pressure set at 3MPa.A cross flow air curtain device with uniform air volume and strong anti deviation ability was designed by combining Anasys Fluent simulation and experiments to study the width of the air curtain outlet,length of the guide groove,type of flow channel(supply air duct),and arrangement of guide vanes.The dust isolation performance of the designed device was tested.Research has shown that when the outlet width is set to1.5cm,the air curtain can maximally block dust in the frontal area,and the airflow distribution in the rear tunnel is relatively uniform,which is conducive to the discharge of fugitive dust;When the height of the guide groove is set to 40 mm,the rectification ability is strongest,and the entrainment effect of the jet process on the surrounding air is weak;When the channel type adopts a wedge-shaped channel,it can maintain stable static pressure inside the pipeline and achieve uniform air supply at the slot outlet;The guide vanes adopt a combination type blade with a lower inclined angle of 45 ° and a upper vertical angle,and are arranged at 4cm intervals,which can effectively reduce the airflow deflection resistance and enhance the anti-interference ability of the air curtain.The dust isolation test was conducted using the developed air curtain device,and the results showed that the air curtain has a blocking efficiency of 62.59% for total dust and 61.91% for respiratory dust,respectively,which can effectively suppress the diffusion of dust.In view of the difficulties in dust control of fully mechanized coal mining face,a dust control technology system based on head-on spray,air curtain and water curtain technology was proposed.The test results show that the dust reduction efficiency of the combined dust reduction technology for respirable dust and total dust can reach 86.45%and 88.96%,which is 11.24% and 9.89% higher than that of the combined dust reduction technology of air curtain and head-on spray,and 23.03% and 23.15% higher than that of the single spray.It was applied in Shoushan No.1 Coal Mine,and the application proved that the highest on-site dust settling efficiency could reach 85.05%,indicating that the water curtain and air curtain linkage dust reduction technology system can effectively combine the technical advantages of head-on spray,air curtain and water curtain,and achieve the full level,multi-level and high-efficiency coordinated dust reduction through the combination of control and reduction.