Mathematical Modeling and Simulation of Cryogenic Liquid Hydrogen Storage

Abstract: Liquid hydrogen is an attractive alternative to fossil fuels in the aviation industry, but storing it both before and during flights introduces many challenges pertaining to the cryogenic liquid conditions required. Having reliable models to predict the dynamical behavior inside the storage tank is therefore of great interest. This thesis covers the development of a low-dimensional model for a liquid hydrogen storage tank capable of describing boil-off and self-pressurization dynamics by taking into account thermal stratification effects brought on by natural convection. The model uses experimentally derived correlations to estimate the flow characteristics and heat transfer of the liquid domain by dividing it into several horizontal control volumes. Additionally it tries to incorporate highly non-equilibrium descriptions of the evaporation/condensation phenomena at the interface and a non-conventional discretization approach to solve for the temperature profile close to said interface is suggested. Validation showed that the model can produce results closely matching experimental self-pressurization data when calibrated parameters are employed, but not necessarily for all experimental setups. Furthermore, the model was successfully utilized to simulate several common storage scenarios and generate data for analysis. Recurring issues with model robustness encumbers the flexibility and usefulness of the model, and as such more work is required on its development.