Simulation of Dustiness in the Blind Drift of Coal Mine

Abstract

Computer simulation of the dustiness in the blind drift of coal mine was carried out. The most probable scenario for the occurrence of dustiness in the blind drift of coal mine, during the operation of mining combine, connected with the shutdown of the irrigation system due to clogging of nozzles, is determined. In this case, the determining factor affecting dustiness is the ventilation mode of operation and the associated air flow rate in the mine. The Fire Dynamics Simulator (FDS) software package of computational fluid dynamics is proposed to be used. The calculations were performed using the Large Eddy Simulation (LES) turbulence model, in the approximation of low Mach numbers (Ma <0.3)(subsonic approximation), the Deardorff model for calculating of the turbulent viscosity, and the model based on the discrete-path Euler-Lagrange method for describing of the two-phase flow. Analytical dependencies and initial data for modeling were determined: geometric parameters of the blind drift, ventilation and dust emission parameters, dispersed dust composition, initial conditions. The adequacy of the computer model developed was verified on the basis of experimental data obtained by testing the dynamics of dust aerosols at the test bench – MGU Shakhtpozhservice LLC. The adequacy of the developed computer model is confirmed based on satisfactory agreement of the simulation results with experimental data. The results of dustiness modeling in the blind drift were analyzed. The distribution of the coal dust mass concentration over the blind drift cross sections for various air flow values of 2.4, 3.6 and 4.8 m3/s is shown. The concentration of coal dust in the area of local ventilation fan jet action is significantly higher – up to 1.8 g/m3 for suspended dust than in the translational movement zone with permissible value of 150 mg/m3. The dependences of the concentrations for suspended and precipitated coal dust along the length of the blind drift were obtained. As a result of dispersed composition analysis, the following were established: the main maxima of the suspended particles size distribution functions by mass correspond to particle diameters of 5-7 microns, in addition, particles with diameters from 20 to 40 microns constitute a significant proportion; significant dust deposition with a diameter of more than 50 microns.