| Mine dust has always been a serious threat to underground production safety and physical and mental health of workers,the country's economic losses caused by dust problems every year amount to several billion yuan,and hundreds of thousands of deaths due to dust or indirect deaths are caused each year,solving the problem of high dust concentration in underground work surface is extremely urgent.As the main dust production source below the mine,dust control aiming at fully mechanized face is particularly important.This paper is to solve the problem of high concentration of dust in fully mechanized face,building a physical model of a single headway that is proportional to an actual roadway,based on that,making study on the coherent swirl flow ventilation flow field structure and pattern of dust diffusion,selection of ventilation parameters based on similar experimental principles,respectively to meet similar sports and dynamics.Based on this physical model,analyzing the relationship between the distribution of dust concentration in the roadway and the air flow rate,the efficiency of the dedusting fan,and the blowing/suction ratio,setting up a theory model of concentration distribution of cyclone dust.To explore optimal ventilation conditions,the paper carried out flow field analysis experiment and dust control effect experiment respectively,in the first experiment,performed ventilation flow field analysis with the help of PIV,choosing 3000 mesh talcum powder as tracer particles,a comparative experiment was conducted to compare the effects of different blowing and sucking flow ratios,strip slot widths,the number of slots,and the position on the structure of ventilation flow field.Came to the conclusion: The smaller the blowing/suction ratio was,the more favorable it was to control the dust in the head area,but it will reduce the swirl effect of rotating the air curtain in the tunnel section,a too large or too small blowing/suction ratio can hinder dust emission,there was an optimal ratio;The width of the seam affected the jet flow state and thus affected the flow structure of the flow in the tunnel;The number of seams affected the swirl strength of the main swirl body,the fewer the number of seams,the higher the swirl strength,the better the effect of blocking the dust diffusion on the section.In the dust control experiment,a comparative experiment was carried out to control the dust under the attached wall cyclone ventilation and direct-blowing air supply,and the effect of installing exhaust hood on dust control and dust removal,effect of roadway shape on dust control and removal in ventilation system,there are the following conclusions: Comparedwith direct-blowing air supply,the attached wall cyclone air supply method can significantly improve the system's dust control effect and can clean the roadway environment,among them,the cyclonic air supply method of the attached wall achieved 96.43% and 99.35% of the dust control efficiency at the driver and the fan duct overlap respectively,comparing 80.41% and95.10% of the direct-blowing air driver zone and overlap zone,the dust control efficiency has improved significantly;The installation of exhaust hoods on the suction outlets had significantly increased the suction strength and dust control capacity of the air ducts,the addition of exhaust hoods had increased the dust control efficiency of the driver area and overlapped sections to 99.61% and 99.81%;The section shape of roadway will have a great influence on the operation of ventilation system.In the unfavorable area of ventilation in rectangular roadway,it will restrict the movement of rotating wind flow,easily accumulate dust,and it had a great influence on the whole ventilation and dust removal of the system.If necessary,a guide was needed at the location when necessary. |
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