Abstract: In order to explore prevention and control measures for gas and coal dust explosion, explosion-proof performance of powder clouds is tested in roadways with large-scale sections. Firstly, an 2 m large pipe and its open space were used to study formation process and dynamic distribution characteristics of powder clouds. On this basis, with explosion pressure and flame velocity as characteristic parameters, gas and coal dust explosion and suppression experiments were conducted in a large roadway with a section of7.2 m². The results show that the powder can cover 7.4 m² section at 60 ms, and most of the powder is ejected at 1 200 ms, forming an effective explosion-proof barrier. When surface density of powder cloud reaches 8.1 kg/m², flame can be completely extinguished within 13 m, and maximum explosion pressure is reduced by 57.0% from 0.293 to 0.126 MPa while pressure rising time at 140 m is delayed by 137 ms. As power concentration increases, suppression effect of cloud curtain is enhanced, and it can extinguish flame in a short distance and greatly attenuate explosion pressure.

Key words: powder clouds, gas and coal dust explosion, explosion suppression, explosion pressure, flame propagation velocity