Research on the flow characteristics and spontaneous ignition mechanism of high-pressure hydrogen in semi-closed T-tube

An accidental leak in the hydrogen transmission pipeline may lead to the spontaneous ignition of hydrogen and cause an explosion, resulting in a disruption of the hydrogen transmission process. This paper proposes applying a bifurcated tube structure to hydrogen tubes to address work stoppages. This article introduces normal blockage and axial blockage based on the direction of airflow. The effects of these blockage types and the relative positions of the bifurcated structure on hydrogen flow characteristics and transmission behavior within the tube are investigated. Research findings show that axial blockage significantly outperforms normal blockage in weakening the leading shock wave. Furthermore, a forward shift in the position of the bifurcated structure enhances the weakening effect on the leading shock wave. Potential mechanisms of spontaneous ignition within the tube are proposed, and the evolution of the flame at the tube outlet is analyzed. Results indicate that a forward shift in the bifurcation position reduces the maximum length and width of the external flame and shortens the time interval between the separation of the external flame and the internal flame. This study provides a valuable reference for the safe operation of hydrogen transmission pipelines and hydrogen refueling stations.