Experimental study on gas explosion and venting process in interconnected vessels

• We investigate the closed and vented explosion characteristics in a interconnected vessels experiment system.
• The worst ignition position is shifting from ignition in the interconnected pipe to the walls of the two vessels.
• The transmission style and interconnected pipe length have significant impacts on the effect of venting on the protection.
• For better venting effect, the use of a divergent interconnected pipe from the big vessel to the small one is advised.
• For better venting effect, it is necessary to reduce the interconnected pipe length as far as possible.

A pilot scale interconnected vessels experiment system was established, and the closed and vented gas explosion characteristics in the system were studied, using 10% methane–air mixture. Regularity of pressure variation in vessels and flame propagation in linked pipes was analyzed. Furthermore, the effects of transmission style, ignition position, pipe length, and initial pressure on explosion severity were discussed. For the closed explosion: explosion in interconnected vessels presents strongly destructive power to secondary vessel, especially transmission from the big vessel to the small one; the worst ignition position is shifting from ignition in the interconnected pipe to the walls of the two vessels; as far as ignition in big vessel is concerned, the peak pressure in secondary vessel increases with the pipe length much faster than that for ignition in small vessel; the peak pressures in two vessels are approximate linear functions of initial pressure. For the vented explosion: the transmission style and interconnected pipe length have significant impacts on the effect of venting on the protection; in order to obtain the better venting effect, the use of a divergent interconnected pipe from the big vessel to the small one in industry is advised and it is necessary to reduce the interconnected pipe length as far as possible or install flame arrester in the interconnected pipe.