Research On Blasting Water Mist Reducing Dust Resulting From Blasting Demolition

Dust resulting from blasting demolition of city building is one of damaging effects of blasting,there are lots of chracteristics in dust resulting from blasting demolition that diffuse velocity very fast,abrupt strong,suspended time in outdoor enviroment long,and influencing range large,thus blasting demolition dust can seriously pollute circumance around spot of blasting engineering. Along with explosion technology building demoliton has been widely applied in the city, enviromental pollution resulting from dust in blasting engineer have been pay attention by total social.This project used explosion energy driving water,made it scattering and atomizing,and formed fine droplets,these droplets could interact with building blasting demoliton dust in movement of high speed,the aim that dust could be captured by water mist at high efficiency would be realized.This paper designed devices of bringing about explosion water mist,set-ups of raising blasting demolition dust,and systems of capturing dust.Adopting theoreical analysis and experimental methods to reseach correlated features of water mist poduced by explosion and blasting demolition dust,this project overally analysized every factor of water mist resulting from explosion influencing on caputuring efficiency of blasting demolition dust.The main work and conclusions of this thesis are as follows:(1) According to experiment results, velocity of impregnation of bentonite is the fastest that is 2.81 millimeter per minute, what is next is mortar power, the third is brickdust, and that of concrete dust is the slowest that is 1.41 millimeter per minute. As a result,birck dust,motar power and concrete power are hydrophobing dust,and bentonite is moderate strength dydrophicous dust.(2) This paper determined the components of simulative dust of blasting demolition and the way of raising dust,test results indicated concentration of blasting clearly varied with time and distance,the high concentration region moved towards to distant place along with time,and concentration of blasting dust more and more low.(3) Using the dust density detector and laser particle analyzer, this paper measured the dynamic distribution characteristics of concentration and particle size of simulative dust, test results indicated that dust greater than 100 micrometer fastly sudsided, and drift distance is from 1 meter to 2 meter, dust slowerly sudsided that their paticle size is from 10 micrometer to 100 micrometer, while dust hardly subsided that there particle size is less than 10 micrometer.(4) By super photography,the diffusing radium,diffusing velocity and water mist floating time of dust in air were studied,research results that that the horizontal dispersal of water mist could be distinctly divided into three stages, near field, mid field and far field under exploding effect of the explosives.In mid field stage,the water obtained higher kinetic energy from explosion of centre charge,the water ch;mged from non-individual body to dispersed body,it continually mixed with air when it spreaded towards outer,and fractured smaller drops. This is main stage that water drop frature.Three stages of diffusing of water mist have respective feature.(5)A system adapt to the high-speed flow field called DPIV is designed and makes it possible measure the distribution of particles in the particle field. Through measuring particle size of water mist resulting from explosion, research results indicated that range of particle size of water mist of resulting from explosion is from 0.15 millimeter to 1.05 millimeter, particle size of most of water drop focused on 0.3-0.5 millimeter.(6) Using devices of bringing about explosion water mist and set-ups of raising blasting demolition dust, this paper studied factors influencing on caputuring efficiency of water mist resulting from explosion.Experimental results showed explosion water mist had good caputuring effect, caputuring efficiency decreased with distance between devices of bringing about explosion water mist and set-ups of raising blasting demolition dust increased,increased with the specific explosive increased,increased and then decreased with increasing ratio of length and diameter,increased with increasing mutual effect time between water mist resulting from explosion and dust. Caputuring efficiency of water mist related to the concentration of dust, it increased and then decreased with increasing concentration of dust ratio of length and diameter,the maximum capacity of caputuring duat is from 600 to 700 milligram.The caputuring efficiency of water mist related to category of dust,as the hygroscopicity of dust was bigger and bigger, The caputuring efficiency of water mist was higher and higher.Figure 92 Table34 Reference 110...