Experimental and numerical study on connecting pipe and vessel size effects on methane–air explosions in interconnected vessels

The size effects on a methane–air mixture explosion in the interconnected vessels were investigated in this article. The vessels were interconnected by pipes of various lengths or diameters. Varied pipe lengths were analyzed by experiment. The results indicate that the maximum explosion pressure and the maximum rate of pressure rise in the primary and secondary vessels increase with pipe length. To investigate the effects of pipe diameter and volume ratio on methane–air mixtures’ explosion in the interconnected vessels, a computational fluid dynamics model was implemented. The model was validated by comparison with experimental results. A fair agreement was observed between the simulation results and experimental data. The simulation results indicate that an increase in the pipe diameter will reduce the danger of explosion. The maximum explosion pressure in both vessels increases when the volume ratio increases. When the primary vessel is larger than the secondary vessel, the maximum rate of pressure rise in the primary vessel decreases with volume ratio. However, the maximum rate of pressure rise in the secondary vessel increases. The maximum rate of pressure rise changes inconspicuously while the secondary vessel is larger than the primary one. Hence, the cubic-root law is not applicable to an explosion in the interconnected vessels. These conclusions can support the safe design of chemical equipment.