Resolving the rollover challenges in liquefied natural gas storage: A review from mechanism studies to advanced predictive approaches

Abstract

This review focuses on state-of-the-art advances in the theory and modeling of thermal stratification and rollover phenomena, which are crucial for the safety and efficiency of cryogenic storage systems, particularly those used for liquefied natural gas storage. Thermal stratification occurs due to temperature and density gradients in the storage tank, while rollover is a sudden and potentially hazardous mixing event triggered by the destabilization of the stratified liquid-liquid layers. The driving mechanisms for stratification and rollover are examined, highlighting key thermodynamic and fluid dynamic principles that govern these phenomena. Advances in numerical simulations are reviewed, with an emphasis on computational fluid dynamics models and their integration with real-time monitoring systems for enhanced accuracy. Recent experimental techniques are also discussed, with a focus on scaled tank experiments and advanced visualization techniques, in the temperature range from a few Kelvins to room temperature. Emerging challenges are summarized and analyzed, including the influence of variable fluid composition, dynamic operating conditions, and the complexity of industrial-scale applications. The review concludes by outlining future research directions, advocating the urgent need for improved theoretical models incorporating machine learning techniques, the establishment of more comprehensive experimental databases, and the implementation of robust safety protocols. This study provides comprehensive guidance for the efficient storage of other cryogenic fluids, such as hydrogen and liquid air, as well as innovative storage systems, including large-scale LNG ships.