Experimental study on thermal stress of cryogenic tank during different cool down process.

An experimental study is performed to investigate the transient thermal stress distribution of an aluminium alloy tank during cryogenic fluid filling processes. Three different filling procedures are adopted with liquid nitrogen being fed into the tank from the top axial nozzle, the bottom axial nozzle, and the top lateral sprayer, respectively. The transient temperatures and thermal strains are measured, and the local thermal stresses are calculated. The results indicate that fluid filling from top axial nozzle leads to the most uniform temperature distribution and the lowest transient thermal stress in the tank wall. Filling from bottom axial nozzle produces similar but much steeper cooling curves and higher transient thermal stresses. However, filling from top lateral sprayer generates a quite different temperature distribution and meanwhile, the highest level of thermal stress. Moreover, the cooling curves become more uneven as the feeding rate increases, resulting in higher transient thermal stresses.