Study on the coupled flame propagation dynamics of hydrogen/air deflagration in interconnected vessels

Hydrogen deflagration in interconnected vessels is more destructive than that in isolated vessels. In this study, a three-dimensional transient model of hydrogen/air explosions in an interconnected device was developed using large eddy simulation (LES). The coupling interactions among flame propagation, pre-compression, and backflow phenomenon were systematically investigated, revealing that the pressure piling originates from the flame–flow feedback between the ignition vessel and the secondary vessel. Moreover, the influences of geometric scale and ignition location were investigated. As the volume ratio increases, the peak overpressure in the secondary vessel rises monotonically, reaching 1414 kPa at a ratio of 14:1. The pipe diameter exhibits a negative correlation with the maximum overpressure, whereas increasing pipe length weakens the pre-compression but slightly enhances the peak overpressure. In addition, ignition in the larger vessel leads to a significantly more hazardous explosion than ignition in the smaller vessel.