Experimental and numerical analysis of the chill-down process of a large horizontal cryogenic storage tank

An experimental system is built to investigate the chill-down process of a 60 m3 horizontal cryogenic storage tank. Accordingly, a numerical model of the chill-down process is constructed to calculate the two-phase flow transition and thermal stress distribution. The chill-down processes with flow rates of 35 L/min and 43 L/min are investigated. The results show that the chill-down process of the wall can be divided into three stages, including slow cooling by cryogenic gaseous nitrogen, rapid cooling by boiling liquid nitrogen, and conduction cooling in contact with liquid nitrogen. Moreover, the maximum deformation in horizontal tanks shifts from the middle to the end of the bottom due to the uneven temperature variation during the chill-down process. The study highlights a positive correlation between the temperature gradient and the stress value. As the liquid accumulates, a large circumferential stress appears at the liquid level, resulting in the maximum stress section at the same height as the liquid level. The maximum stress except the constraint is about 248 MPa at a flow rate of 43 L/min. Overall, the analysis of the experimental and simulation results in this work provides useful information and guidance for the safe use of large horizontal cryogenic storage tanks.