Experimental Study on Coal Dust Explosions in a Large-scale Tube

It is significant to study the propagation properties of coal dust explosions by experimental method for the understanding and preventing of coal dust explosion accidents in mining.The propagation of explosion pressure wave in coal dust-air mixture was investigated in a self-made tube with an inner diameter of 199 mm and length of 29.6 m.Piezoelectric pressure sensors were used to record the pressure histories at different points along the tube during the pressure wave propagation process.The influences of coal dust particle size and coal dust concentration on explosion overpressure were also discussed.The experimental results show that the propagation of coal dust-air mixture explosions under weak ignition conditions is achieved.The propagation velocity of the pressure wave along the tube is between 400 and 430 m/s,and the maximum overpressure of coal dust explosion in the tube is at the range of 68 to 72 kPa.The explosion overpressure increases with the decreasing of coal dust particle size,but the influence of coal dust particle size on explosion overpressure gradually diminishes with the increasing of coal dust concentration.