A CFD model for the Multipurpose Hydrogen Test Bed (MHTB) Ground-Based Self-Pressurization and Pressure Control Experiments

摘要

This paper presents a CFD model for simulating the self-pressurization of a large scale liquid hydrogen storage tank. In this model, the kinetics-based Schrage equation is used to account for the evaporative and condensing interfacial mass flows. Laminar and turbulent approaches to modeling natural convection in the tank and heat and mass transfer at the interface are compared. The flow, temperature, and interfacial mass fluxes predicted by these two approaches, during tank self-pressurization, are compared against each other. The ullage pressure and vapor temperature evolutions are also compared against experimental data obtained from the MHTB self-pressurization experiment. A CFD model for cooling cryogenic storage tanks by spraying cold liquid in the vapor region is also presented. The Euler-Lagrange approach is utilized for tracking the spray droplets and for modeling interaction between the droplets and the continuous phase (vapor). The spray model is coupled with the VOF model by performing particle tracking in the vapor, removing particles from the vapor domain when they reach the interface, and then adding their contributions to the liquid. Only droplet-vapor heat transfer is included in the model. The flow, temperature, and interfacial mass flux predicted by the model are presented. The ullage pressure is compared against experimental data obtained from the MHTB spray bar mixing experiment.