Abstract:

Respirable dust in coal mine operation space seriously endangers the health of workers. The existing pneumatic spray technology is not effective in reducing and removing respirable dust. To this end, a new supersonic pneumatic atomization technology was developed. The atomization characteristics were studied by experiments and numerical simulation. The transient dust reduction performance of this technology was compared with that of supersonic siphon and internal hybrid pneumatic atomization dust reduction technologies through multi-scale experiments. The results show that the high-speed fine mist domain is formed in the spray field of the new supersonic pneumatic atomization nozzle, and the droplet size and velocity gradually increase with the increase of spray distance. Compared with supersonic siphon and internal mixing pneumatic atomization nozzles, when the pneumatic pressure is 0.3-0.4 MPa and under different water flows, the new nozzles have smaller droplet size, higher droplet movement speed, and higher dust reduction efficiency, which can reach up to 90%. With the increase of pneumatic pressure, the range of high-speed fine mist area formed by the new nozzle increases, and the concentration of micro-mist increases, so that the dust reduction efficiency of small particle size dust increases at different times. When the pneumatic pressure is 0.4 MPa and the water flow rate is 10 L/h, the dust reduction effect of 2.5-10 μm respirable dust is the best.

Key words: supersonic pneumatic atomization, atomizing nozzle, atomization characteristics, dust reduction performance, high-velocity fine fog