Effects of Air Outlet Position and Air Speed on Airflow and Dust Field Distributions

Abstract

To meet the actual demands on ventilation and dust removal in mine heading faces and to reduce the potential safety threats and pollution risks of dust, this study investigates the migration and distribution trends of airflow and dust fields at different air outlet positions and air speeds under scenarios using forced ventilation and long-forced-short-exhaust ventilation techniques at the heading face under continuous mining operation, which is accomplished in the engineering context of Xiaobaodang Coal Mine by a combination of two-phase flow analysis and finite element simulation. As the results reveal, the return air speeds exhibit a “rising-falling-stable” trend at different air outlet positions and inlet air speeds. Appropriate increase of inlet air speed is effective in covering the front corner area and in improving the dust distribution in the roadway. Dust concentration on the return air side is markedly higher than on the air duct side, with distribution primarily in the front section. In the case of forced ventilation for the roadway having a large cross-sectional area of 22 m2, reasonable dust distribution on the return air side can be ensured when the air duct outlet is 10 m away from the front and the inlet air speed is 11 m/s. In the case of long-forced-short-exhaust ventilation, reasonable settings are a 15 m distance of air duct outlet from the front and a 9 m/s speed of inlet air.