Research on dust diffusion and settlement law of different particle size in fully mechanized excavation face

Based on theoretical analysis, numerical simulation and field test, the dust migration and distribution law along the roadway of fully mechanized excavation face are studied through the three-dimensional numerical model. Based on the filter membrane weight method, the dust mass concentration of fully mechanized excavation face was measured, and the particle size analysis of filter dust collected on site was carried out from the point of view of dust particle size. The results show that the dust of fully mechanized excavation face is mainly concentrated in the range of 5 m away from the heading face, and under the action of air flow, the dust mainly migrates to the rear along two paths: one is between the coal wall of return air side and the body of roadheader, the other is between the body of roadheader and the roof of roadway; the dust settlement along the fully mechanized excavation face can be divided into rapid settlement area, medium speed settlement area and slow settlement area; the dust with a particle size greater than 50 μm is easy to settle in front of the roadheader driver; the "inflection point particle size" during the dust settling process is 40 μm, and the dust smaller than the "inflection point particle size" is not easy to settle in the roadway.