The Study On Relationship Between The Effection Of Wind-break Wall Of Dust And The Bulk Material Properties

With the rapid economic and industrial development, the number and size of open bulkstockpile are increasing, at the same time, environmental protection as the country increasinglyhigh demand, more attention has been paid for the environment pollution of bulk material heap ofdust. How to suppressing the bulk material dust, protecting environment, saving energy becamethe desiderate problems to be solved. There are many ways for bulk material dust suppression,this paper mainly for dust suppression effect of the break wall and bulk material characteristic.First, by numerical simulation in a high degree of operating conditions of the different winddeflector and wind deflector behind the flow field changes to explore of the energy loss andpressure loss of the wind speed behind the windshield within a certain distance. Then, through theexperimental study to explore the effect of different bulk material density, particle size, windspeed and wind deflector height on bulk materials piled up the quantity of dust, received thefollowing conclusions:1) After the flow goes through the wind deflector, the wind speeds of the bulk materialdownwind side will be gradually increasing from the bottom of the bulk material up, andthe maximum value is obtained at the top of the bulk material.2) When the wind goes through the wind deflector, forming strong flow around and seepage,keeping a low speed between the wind deflector and the bulk material, and there is a highspeed of the area at the top. The weed of flow around gets around the wind deflector, andthen speeds off the calculation area directly. The weed of seepage passes through thewind deflector then continues to flow down. When it gets the bulk material, the weed willflow up along the bulk material downwind side, and emerges the separation of speedboundary layer. A part departs form the calculation area following flow around, anotherpart forms speed recirculation region in the lee side.3) Dust emission of the bulk material decreases with the grain size increasing overall,however when bulk material particle size is too small, the surface glue and cohesioneffect of particles is more sensitive than that of big particle. With the action of superficial water, cohesion between particles increases, which lead that wind speed causing value ofsmall size particle is higher than the big one, so the wind speed causing increases slowly,with particle size increasing at this size range4) The same size of bulk material, dust emission of the bulk material is proportional to weedspeed.5) In the same size, dust emission of the bulk material is inverse ratio with bulk materialdensity.6) When the ratio of the wind deflector height and bulk material height is less than9/7, dustemission of the bulk material decreases strongly with the wind deflector height increasing,and when the ratio of the wind deflector height and bulk material height is greater than9/7. So for certain heights of bulk material it is best that the wind deflector height is9/7as high as bulk material height in the actual project.7) By analyzing and recognizing empirical datum, formulate empirical formula of dustemission of the bulk material and the wind deflector height, the bulk material height, bulkmaterial particle size and weed speed.