Dust removal effect of negatively-pressured spraying collector for advancing support in fully mechanized coal mining face: Numerical simulation and engineering application

摘要

Combining experimental measurements and field tests, a negatively-pressured spraying collector was developed for the dust source of advancing support in fully mechanized coal mining environments based on the results obtained from the numerical simulation of wind-dust diffusion law under the action of dust collector using discrete particle model of Computational Fluid Dynamics (CFD) in order to reduce dust from advancing support. Simulation results showed that advancing support produced a dust band with high concentrations of up to 1,000 mg/m(3) near the sidewalk around 0-9 m away from the wind leeward side of the advancing support which gradually diffused to 0-36 m. After the use of negatively-pressured spraying collector, the concentration of dust band at the leeward side of the advancing support was decreased to below 300 mg/m(3) and diffusion extent shrank to 0-5 m from the leeward side of shearer; the form of dust mass near sidewalk also changed to low concentration dust band. After laboratory tests, ultrasonic atomizing nozzle was selected as the final nozzle and negatively-pressured spraying collector equipped with this nozzle was applied under the same water and air pressures of 0.4 MPa which gave effective range of 5.03 m and atomization angle of 71 degrees. The developed negatively-pressured spraying collector was applied to 73(dow)(n)23 fully mechanized coal mining environment in Nantun mine and it was found that it effectively decreased dust concentration from advancing support in the operation zone near sidewalk. Average total and respiration dust-decreasing rates were up to 81.5% and 79.1%, respectively, which confirmed excellent dust reduction efficiency of the proposed device.