Small-scale experimental study of vaporization flux of liquid nitrogen released on ice

Abstract

One of the LNG accident scenarios is the collision of an LNG carrier on an iceberg during marine transportation. A collision can result in damages to the vessel and lead to the leakage of the contents on ice or an ice-water mixture. When cryogenic liquid comes in contact with ice, it undergoes rapid vaporization due to the difference in temperature between the ice and cryogenic liquid. This process is different from the heat transfer between water and cryogenic liquid as ice is a solid and thus heat transfer to the pool occurs primarily through conduction. In this paper, the heat transfer phenomenon between ice and cryogenic liquid was studied through a small-scale experiment and the resulting vaporization mass fluxes were reported. The experiment involved six spills with varying amount of liquid nitrogen on different ice temperature to determine its effect on vaporization mass flux. The vaporization mass fluxes were determined by direct measurement of the mass loss during the experiment. The results indicated that the vaporization mass flux was a function of release rate and ice temperature. When the release rate and ice temperature was high, the vaporization mass flux follows a decreasing trend. With further reduction in release rate and ice temperature, the vaporization mass flux was found to be independent with time. The one dimensional conduction model was validated against experimental results. The predicted temperatures and heat flux were found to be in good agreement with the experimental data.