Hydrogen leakage and diffusion in the operational cabin of hydrogen tube bundle containers：A CFD study.

The operational cabin of hydrogen tube bundle containers (HTBCs) is susceptible to vibration and fatigue loads during transportation, which may result in hydrogen leakage and deflagration accidents. In this paper, a three-dimensional (3D) computational fluid dynamics (CFD) model is developed to simulate the effects of leakage diameter, leakage pressure, leakage direction and position on hydrogen leakage and diffusion in the operational cabin of HTBCs. The results demonstrate that the formation of vortex recirculation zones leads to the accumulation of flammable gas cloud (FGC) in the operational cabin. The medium leakage diameter (1.5 mm) and higher leakage pressure (20 MPa, 35 MPa) cause the operational cabin to be filled with FGC within 5 s, requiring the operational cabin to be designed with no possible ignition source inside. In addition, when hydrogen leaks from the +Z direction, the sensor responds within 0.31 s, which is 1.7 s earlier than the response time in the -Z direction, indicating that the existing sensor layout cannot meet the requirements of fast response. When the leak position (L 3) is close to the vent, the FGC volume proportion at 2 s is 19.3 % and 15.88 % lower than that of L 1 and L 2 , respectively, indicating that the leak position close to the vent can effectively slow down the accumulation of FGC. The research results have implications for the safety design of operational cabin of HTBCs, the layout of hydrogen sensors and vents, and the emergency response measures for hydrogen leakage. [Display omitted] • Numerical simulation reveals hydrogen leakage and diffusion behavior of tube bundle containers during transport. • Vortex recirculation zones cause flammable gas cloud accumulation in operational cabins. • Medium leakage (1.5 mm) and high pressure can fill the cabin with flammable gas cloud in 5 s. • Leakage direction and position affect hydrogen sensor response time. • The addition of hydrogen sensors and vents can reduce the risk of explosion. [ABSTRACT FROM AUTHOR]