Numerical investigation on the filling capability of large scale vessels for ground hydrogen storage

In this work, a numerical investigation on the filling capability of large hydrogen vessels type I, designed for ground installation, is presented under varying operating conditions, namely the initial pressure and temperature, and the mass flow rate. Two-dimensional axisymmetric, conjugate heat transfer, unsteady Reynolds averaged Navier–Stokes based discretization has been adopted. The accuracy of the numerical model is discussed against experimental results already available in the open literature. Results are presented to study the flow field and heat exchange phenomena in very high length to diameter ratio vessels. Different filling scenarios are considered to discuss physical issues connected to gas injection and the storage capacity a function of operating condition, vessel scale, and filling strategy. The obtained results highlight that severe temperature hot spots may affect the gas, but without impacting on the vessel itself. The gas heating up can be related to the residence time and the related capacity reduction can be considered in order to evaluate and plan effective filling strategies.