Premixed flammable gas explosion in containers connected by pipes with different lengths

Premixed flammable gas explosion tests were carried out in two spherical containers connected by pipes with different lengths to determine the history of explosion pressure and the flame propagation velocity in pipes. Effect of pipe length, flame propagation direction, and ignition location on explosion pressure and flame propagation velocity in pipes was investigated. Experimental results show that the explosion pressure and the maximum rate of pressure in the second container are enhanced with the increase of pipe length. In the second container which is smaller, the pressure enhancement is more apparent with stronger pressure oscillation. The increase in pipe length has little effect on the explosion pressure in the first container. The flame velocity in pipes accelerates first and then slows down when approaching the second container. For the fixed pipe diameter, the initial flame velocity in pipes approaching to the first container increases with the container volume. As the volume of the second container decreases, the resistance to the flame propagation increases and the flame velocity in pipes near the container slows down, accordingly.