Research On Unsteady Migration Law Of Dust And Design Of Dust Control System In Blasting Tunnelling Space

In order to determine the dust migration law in blasting tunnelling face and design the dust control system for the 1100 Working Face, it conducts the experiments such as airflow distribution, dust diffusion, dust settlment and dust concentration versus time. After building a geometric model at a ratio of 1:1, it creates and modifies mesh of the model and chooses a optimal tubulence model-RNG k-e. Trough simulating by the CFD software, it gets the dust migration law as follows at the distance L=0-60 m to the working face. As L increases, the wind velocity first increases and then decreases. Dust concentrition decreases with the increase of the vertical height at 0.5-4 m, and first increases and then decreases with the increase of L.Dust particls with diameters less than 10 μm uniformly distributes in space, and the settlement quantity shows a trend of "decrease-increase-decrease-increase" with the increase of L. For the dust particls with diameters at 10-200 μm, the settlement quantity shows a trend of "decrease-increase-decrease" with the increase of L. Dust particls with diameters at 90-200 μm almost completely settles. In the early blasting operations within 5 min, the dust concentration along the roadway sharply declines, and gently declines in 10-50 min. The high concentrition area stays within L=40 m and dose not migrates along the roadway. L=10-20 m is airduct jet vortex area, in which the settlement quantity of dust particls with diameters at 10-200 μm is relatively fewer, and the dust concentration is relativly higher in a long time.It chooses water mist united with dedusting fan to control the dust. At L=24 m,29 m and 34 m, there are three sets of spraying devices forming water curtains to restrain the dust diffusion. The suction inlet of the airduct is set at L=15 m, forming a negative pressure export in the center of the flow field vortex, which is in favour of air auction and purification.