Heat transfer study on cryogen evaporation in stationary and moving tank

Abstract The thermal characterisation of cryogenic fluids is quite important during their storage due to external heat leaks. Due to their low viscosity, cryogens are prone to large liquid motions w.r.t the container due to external disturbance (sloshing) during transportation. This phenomenon causes a higher internal heat generation rate due to viscous dissipation. In addition to this, the thermal stratification in the cryogenic storage container is disturbed. In the present work, as a first step, a transient two-phase thermodynamic model, for a stationary liquid nitrogen cylindrical tank, is developed for two cases, first to understand the boil-off rate (isobaric condition /vent open) and second to measure transient pressure evolution (closed condition /vent close) due to external heat in-leak. Experiments are carried out in both stationary and moving (slosh) conditions of the cryogenic tanks to see the change in evaporation rate in the vent open condition of the tank. Thermal stratification in both liquid and vapour phases is studied for the stationary condition of the cryogenic tank. Experiments are also performed to measure the pressure evolution inside a 110-liter and 25-liter cryogenic tank in stationary conditions.