Choosen And Optimiation Of Spraying System On Support For Dust-Laying In Fully-Mechanized Caving Face

Compared with other caving faces which are not using the fully-mechanized caving method, the fully-mechanized caving face produces much larger amount of dust than others. Therefore, in consideration of mine workers' occupational safety and health, and the enterprise's safety management, we must ensure that the dust concentration in the working face is controlled under the allowable range of our regulations. On the basis of the mechanism research of nozzle spraying, the measurement of the particle size of droplet which produced by nozzle atomization, the dust examination on the working face and the simulation of dust along the whole working face, the author puts forward a optimized dust-laying system of support spraying, and it has obtained a good dust-laying effect dust-laying work.Based on the mechanism of atomization broken and two-phase flow theory, the influent parameters of spraying, the equations for calculating the velocity of the liquid jet, the survival time of the particle in the atmosphere and the efficiency of the dust-laying by liquid droplets were obtained. Then, by comparing a number of modern laser measurement equipments, this dissertation chose Winner 313 system to measure the particle size distribution of different nozzles under different water pressure. Therefore, by comparing particle distribution of the spraying under different water pressure, and the nozzle's outlet velocity simulation get by Ansys, which is a software for mechanical simulation, a proposal of the application of 1.5mm nozzle, 8Mpa water pressure on the spot was put forward.On the basis of the measuring of dust distribution in the working face before and after spraying, this dissertation analyzed and elicited the regulation of the dust concentration along the fully-mechanized caving face. Depend on the simulation of the dust around the shearer and drawing opening, the starting number of the support spraying system in the leeward of shearer was confirmed.Based on this study, a support nozzle spraying system which suited the Dongtan coal mine' situation was put forward. By comparing the different arrangement of the dust-laying system, some optimal parameters, such as arrangement, water pressure, etc. were determined. By the experiment of the dust-laying efficiency on the working face, the optimized spraying system has a good efficiency in dust-laying work.