Experimental and numerical investigation of self-pressurization with different methods of insulation for ground and space applications

Abstract

The necessity of precise estimation and understanding of self-pressurization in a cryogenic storage vessel has increased rapidly over the years because of the influence of self-pressurization phenomena on the design of cryogenic engines. Since propellants are stored at their boiling temperature or subcooled condition, very small heat infiltration itself causes self-pressurization. When heat is transferred to the propellant tank, the liquid near the sidewall is heated up, and a warm stratified layer is developed at the liquid vapor interface, which causes self-pressurization. A numerical model is developed, and experiments are conducted to investigate the self-pressurization effects of cryogenic storage vessels to precisely understand the mechanisms causing it and the effect of methods of insulations, including multi-layer insulations in tanks. The numerical model is developed based on the available correlation to predict the self-pressurization and related parameters of a double wall cryogenic storage tank with different sets of insulations such as air, foam, vacuum, and MLI and different cryogens; hydrogen, nitrogen, and oxygen. A double wall cryogenic storage tank using SS 304 is also developed, conducted self-pressurization studies using liquid nitrogen under different methods of insulation. The experimental results were compared with the numerical model and found in good agreement. Comparing the self-pressurization rate of different cryogens, the value is higher for hydrogen. Since the boiling point of hydrogen is less, the axial heat flux acting will be higher. The low-density fluids will quickly move towards the interface and deposit, causing a warm layer at the liquid-vapour interface. The amount of phase change is also higher for liquid hydrogen, which in turn aid in rapid self-pressurization. Among the insulations used, multi-layer insulation shows the best performance in terms of thermal resistance. The analytical and heat transfer model developed predicts and compared well with the experimental results and can be used for a variety of situations in ground and space for self-pressurization and roll over phenomenon studies and prediction of results in advance.