Experimental and Numerical Investigation of Stratification and Self pressurization in a High Pressure Liquid Nitrogen Storage Tank

This paper discusses the evolution of stratification and self-pressurization in a cryogenic storage tank. The heat ingress due to the large temperature difference between ambient and cryogen leads to thermal stratification and self-pressurization. The prediction of the thermodynamic state of cryogen is required for the successful execution of any space mission. An experimental cryogenic test tank which is a combination of an evacuated vacuum jacket and multilayered insulation has been designed, fabricated and is used for stratification studies using liquid nitrogen as the model propellant. Stratification at two conditions were tested; 'venting' and 'non-venting'. During venting condition, only saturated boiling occurs, and the degree of thermal stratification is very less. Whereas during non-venting condition, there is a significant amount of thermal stratification and the degree of thermal stratification increases with working pressure. For a deeper understanding of the phenomenon and better prediction of the state of cryogen, a numerical model had been developed and validated with the experimental result. A stratification parameter has been used to quantify the degree of stratification for both venting and non-venting conditions. The model developed can be used for accurate prediction of the state of cryogen.

Automated summary

This paper discusses the evolution of stratification and self-pressurization in a cryogenic storage tank. An experimental cryogenic test tank and a numerical model have been used to study and accurately predict the thermal stratification of cryogen.