Experimental research on secondary blasting of coal dust and gas induced by gas explosion

For systematically studying the related regularity of secondary blasting of coal dust-air mixture induced by gas explosion,experiments were done in a horizontal explosive pipeline with four coal dust concentrations. The gas explosion in high-pressure chamber was used to produce shock wave which can wind the coal dust or coal dust and methane mixture pre-set in low-pressure chamber. The results show that explosion pressure of secondary blasting first increases and then decreases as coal dust concentration increases,that maximum pressure for secondary blasting appears at 200 g / m3 of coal dust concentration,and that200 g / m3 coal dust-2% CH4-air mixture explosion pressure is about 0. 441 6 MPa,or 0. 08 MPa higher than that of 200 g / m3 coal dust-air mixture. The explosion pressure increases with volume fraction of methane from 1% to 2%.