Experimental Study on Boiling Vaporization of Liquid Hydrogen in Nonspreading Pool

Abstract

Research on the boiling vaporization process of liquid hydrogen spilled on solid ground is very important for the safety risk assessment of liquid hydrogen. Since the main source of the heat flux in the vaporization process comes from the ground, the heat flux from the ground into the liquid pool should be studied in-depth. In this paper, the boiling vaporization process of liquid hydrogen on the surface of concrete is studied. The analysis of the boiling process of a liquid pool is conducted by utilizing the boiling curve and historical temperature data collected in close proximity to the surface of the concrete. It was found that the boiling regime of a liquid hydrogen pool on the concrete surface presents non-uniformity, and the film boiling of liquid hydrogen on the concrete surface ended earlier than the results calculated by boiling regime correlations. When the measured temperature in the experiment indicates a transition from film boiling to the transition boiling, the temperature difference between the thermocouple temperature measured at a depth of 2 mm and the boiling point of liquid hydrogen is 130 K higher than the predicted superheat of the minimum heat flux (MHF). In the later stage of the experiment, the average relative error between the experimental value of the vaporization rate and the predicted value of the model is 7.48%. This research advances the understanding of heat transfer between concrete ground and a liquid hydrogen pool. In addition, the experimental data obtained in this study contributes to improving the source term model for safety analysis of liquid hydrogen spills.