Investigation of Tank Pressurization and Pressure Control-Part II: Numerical Modeling

A multizone model is used to predict both the self-pressurization and pressure control behavior of a ground-based experiment. The multizone model couples a finite element heat conduction model of the tank wall to the bulk conservation equations in the ullage and the liquid. Comparisons are made to the experimental data presented in a companion paper. Results suggest that the multizone model can predict self-pressurization behavior over a variety of test conditions. The model is also used to predict the pressure control behavior when a subcooled axial mixing jet is used to thermally destratify and cool the bulk liquid. For fast jet speeds, the multizone model does a reasonably predict the pressure collapse behavior. Comparisons were also made between the data and a homogeneous thermodynamic model. These comparisons highlight the deficiencies of the homogeneous modeling approach.