| Fire is one of the major disaster in coal mining,which seriously threatens the safety in production of the mine,Especially for tunnel fire in coal mine,Because of its narrow space,and a large number of toxic gases produced by combustion which seriously endanger the safety of miners,the air flow disorder occurs in the tunnel in severe cases,which often cause more severe damage.Being a new type of fire prevention and control technology,Water mist was widely used due to cleanness,high fire extinguishing effectiveness,low cost,and safety to human and equipment.In recent years,research of application of water mist technology in tunnel have conducted by some scholars.In order to develop the application of this technology in tunnel fire,Research of the characteristics and fire suppression of water mist in modeling tunnel by experimental,numerical simulation and theoretical analysis in this paper.Firstly,the atomization device of water mist was constructed,Meanwhile the optimum working parameters of atomization device is determined by laser particle size analyzer,which analyzes the critical condition of a fine water mist with nitrogen atomization and size distribution regular under the condition of the different inlet flow rate,air pressure and the different in fluent flow rate,water pressure.Secondly,A small-scale modeling tunnel was established,and the experiment on the diffusion characteristics of water mist under different ventilation conditions was carried out.Furthermore,the differential equation of the water mist droplets in the modeling tunnel were deduced by analyzing the force of water mist droplets in the transverse airflow,The diffusion characteristics and its influence factor were elaborated.Moreover,the experiment was carried out for extinguishing Kerosene fire by water mist under the different ventilation of the tunnel based on the modeling tunnel experiment platform.some parameters such as the water mist particle size,fire intensity,ventilation velocity,the modeling tunnel ventilation and its tilt angle were changed for testing the effectiveness of water mist suppression in different conditions,the factors of extinguishing effect of water mist in tunnel fire were analyzed,and the relationship between the characteristic parameters of water mist and the effectiveness of fire suppression were summarized.The experimental work adds theoretical content in the nitrogen water mist to restrain the tunnel fire,and grasp the effect of water mist in different conditions,enrich the experimental research on fire prevention of water mist,In addition the study is helpful for application of water mist in coal mine. |
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