EXPERIMENAL AND NUMERICAL INVESTIGATION OF THERMAL STRATIFICATION DURING VENTING ON A CRYOGENIC STORAGE

Abstract

Over the years, the need for exact estimation and comprehension of thermal stratification and self-pressurization in a cryogenic storage has grown, as the stratification phenomenon is dependent on the architecture of the cryogenic storage. The cryogenic engines use liquid fuels that are stored in liquid form at extremely low temperatures. Since propellants are stored at their boiling temperature or

subcooled condition, small heat infiltration can cause thermal stratification and self- pressurization. When heat is transferred to the propellent tank, the liquid near to the

side wall is heated up, and a boundary layer will develop. The warm fluid inside the boundary layer will move upwards and is dumped at the liquid-vapor interface. The warm fluid layer developed at the liquid-vapor interface is known as a thermally stratified layer, and this phenomenon is known as thermal stratification. Experiments are carried out to examine the effects of self-pressurization and temperature stratification on cryogenic storage tanks in order to avoid stratification. As a result, the current research work aimed to improve the understanding of the combination of thermodynamics, fluid dynamics and combined heat transfer phenomena of cryogenic propellant tank pressurization, thermal stratification. An experimental setup was developed to study the stratification. A cryogenic storage tank with foam insulation has been designed, fabricated, and used for the stratification studies, using liquid nitrogen. To support the experimental findings, a numerical analysis was done using the ANSYS FLUENT software. The model is validated with the experimental result. The Volume of Fluid (VOF) method is used to predict the liquid-vapour interface movement.