Effects of some key-parameters on the thermal stratification in hydrogen tanks during the filling process

• Published in: International journal of hydrogen energy Vol. 44; no. 26; pp. 13569 - 13582
• Main Authors: Melideo, D., Baraldi, D., De Miguel Echevarria, N., Acosta Iborra, B.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 21.05.2019
• Subjects: CFD; Fast filling; Hydrogen refuelling station; Hydrogen storage; CFD; Hydrogen refuelling station; Hydrogen storage; Fast filling
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2019.03.187

Computational Fluid Dynamics simulations are performed to investigate the effect of relevant parameters on the temperature field during the filling process of hydrogen tanks. The injector direction, the injector diameter, and the initial/ambient temperature affect the dynamics of the temperature distribution in the gas and in the tank material during the process. The development of potentially detrimental phenomena like thermal stratification and temperature inhomogeneity could occur, depending on the interactions of the effects of the 3 parameters. One of the most relevant findings is that, depending also on the other conditions, the injector direction can have a significant impact on the thermal stratification and on the critical parameters which provide an indication on the occurrence of stratification like the flow velocity at the injector exit and the Richardson number. The upward direction of the injector contributes to completely avert or at least reduce/delay the thermal gas stratification compared to injectors with a straight or downward direction. •The higher the initial temperature Tini is, the stronger is the stratification.•Gas temperature difference between top and bottom increases linearly with Tini.•Stratification increases with the downward injector; it reduces with an upward one.•Critical flow velocity and Richardson number are affected by injector direction.•With small diameters and upward direction, stratification is reduced or averted.