Study On Dust-Isolation Technique With Air Curtain At Fully Mechanized Working Face

At present, the production of coal mine underground which uses more and more mechanized equipment improves the productivity to some extent.However, in the process of coal mining, it is a proven fact we can not deny that it will produce more dust, which will seriously do harm to the health of underground workers.In addition, those dust will explode and cause accidents under the certain conditions.In spite of the various prevention measures which have been taken in the current mine production, the problem has still not been effectively resolved for the drivers in high dust concentration.In this thesis, we designed the air curtain which can isolate dust and cut off the affect for drivers caused by the big drum of cutting coal dust so that achieve the purpose of reducing dust concentration distribution in working area for drivers.Pipeline blast theory and analysis of uniform flat jet theory, the design should ensure that the air curtain air curtain is ejected from the outlet out of the Merry average, relatively stable.Calculation of isolating dust air curtain outlet of the slit width, wind speed and air flow ejected entraining air flow around the numerical relationship between the proposed isolating dust air curtain outlet of the slit width, there is an optimum wind speed value to guarantee the achievement of a barrier cutting coal dust generated by diffusion to the destination driver work area.Through the simulation calculation of ANSYS numerical and the analysis of the wind speed distribution rule as well as dust concentration distribution of fully mechanized working face airflow.The conclusion are the following:the shearer is one of the main factors to the effects of surface wind speed distribution due to the space section size change suddenly.The size of the inlet velocity for working face,not only affects the average dust concentration, but also affects the diffusion range of dust.The working surface wind speed is big, the average concentration of the dust in the work is small and the dispersion of the dust becomessmaller.However, the wind speed is too large and it will lead to a fall in the dust of the plate which will be raised again.The amount of the dust in the shearer drum will also affect the average dust concentration while it has little effect on the range of dust diffusion.Through the numerical simulation of the air curtain dust, the design of parameters are optimized.The conclusion is the following: the installation position of the air curtain should be with the upper hand side of the drum level of the frontier as far as possible.Air curtain slit outlet should be equal to the width of 0.02 m, the size should be equal to 6m/s, the air should be tilted 5-10°.According to the results of numerical simulation, the concrete mode of air curtain is designed and manufactured.The internal air duct of the air curtain is a wedge shaped and the outlet is guided by the air guiding plate so that the airflow from the air curtain to the tunnel is relatively uniform.Visual experiment was carried out for dust and the air curtain flow has been tested.As the result, it has obtained good results for observing the airflow.