Hydrogen explosion characteristics in the obstructed chamber by changing blockage ratio among adjacent obstacles.

Using the experimental and large eddy simulation (LES) methods, the impacts of equivalence ratio and adjacent obstacle blockage ratio on flame propagation, flame moving velocity, and explosion overpressure in a closed obstructed duct are investigated. The results indicate that the developed LES method is able to reproduce the tendency of flame propagation, flame moving velocity, and explosion overpressure of BR = 30%, 50%, 70% and BR = 70%, 50%, 30%. The early flame propagation and flame moving velocity are not affected by the first obstacle. As the explosion flame passes through the three obstacles, the flame acceleration and deceleration occur in sequence due to the decreasing cross-section and vortex-flame interaction, eventually forming three ascending peak flame moving velocity. The higher vorticity magnitude of BR = 70%, 50%, 30% and BR = 30%, 50%, 70% is mainly concentrated in the early stage and later stage of hydrogen explosion, which directly results in the fact that the flame acceleration and rise rate of explosion overpressure of BR = 70%, 50%, 30% is higher than that of BR = 30%, 50%, 70%. Additionally, the maximum value of flame moving velocity and explosion overpressure of BR = 30%, 50%, 70% is higher than that of BR = 70%, 50%, 30%. • Flame propagation and explosion overpressure are experimentally obtained. • LES method is established to predict flame propagation and explosion overpressure. • The velocity vectors and vorticity magnitude are analyzed. [ABSTRACT FROM AUTHOR]