Influence of Ignition Position on Explosion Characteristics in Linked Vessels with a Concentration Gradient

This study examines the influence of ignition position on explosion characteristics in linked vessels with a methane concentration gradient, aiming to support the safety of industrial combustible gas storage systems. A numerical simulation method was adopted, using a vessel-pipe-vessel linked device. Explosion parameters including pressure, pressure rise rate, temperature, and flame propagation speed were analyzed, with mechanism insights drawn from methane consumption rate and Reynolds number. Results indicate that maximum explosion pressure always occurs in the small vessel, decaying exponentially with increased dimensionless length of the ignition position, and ignition in the large vessel results in significantly higher pressure. The maximum pressure rise rate, maximum temperature rise rate, maximum flame speed, and maximum methane consumption rate each follow a quadratic trend, first decreasing and then increasing with the dimensionless length of the ignition position. Flame propagation is dominated by pipe acceleration, peaking at one end of the pipe near the small vessel at velocities up to 600 m/s. Turbulence intensity increases linearly with the dimensionless length of the ignition position and is highest when igniting in the small vessel. This research clarifies the influence mechanism of ignition position and provides theoretical support for the explosion prevention and control of linked vessel systems with concentration gradients.