Hydrogen energy has been widely used in various industrial processes. However

hydrogen explosion can cause significant loss of personnel and property

and explosion venting is an effective method to reduce the explosion damage. The mechanism of hydrogen explosion venting has become an important research topic in hydrogen energy safety engineering. This study employs numerical simulation to explore the impact of vent parameters on the hydrogen-air explosion dynamics. A geometric model considering internal and external explosion is established. Results show that venting efficiency improves as the vent is positioned closer to the ignition or the number of vents increases. The peak internal overpressure increases by 1.2 times as the single vent moves from the ignition to near the end. The external explosion overpressure and dynamic pressure grows with the decrease of internal explosion venting efficiency. The flame front deflects toward the vent and ejects from the duct under the suction effect of the vent. The vortex flow characteristics near the vent cause the flame to deform as it propagates downstream. Vents located closer to the ignition induce the formation of a reverse flow field and lead to reverse propagation of the flame. The formation of symmetrical vortex regions within the flame causes it to compress

resulting in a longer external flame length as the vent is located farther from the ignition. The maximum flame speed increases by 1.1 times as the single vent moves from the ignition to near the end. Multiple flame propagation speed are exhibited under multiple vents conditions.