Progress and trends in liquid hydrogen release

Liquid hydrogen (LH2) is a promising method for large-scale, long-distance storage and transportation of green energy. However, LH2 leaks pose significant safety risks, such as fire and explosion, due to the rapid formation of gaseous hydrogen. Therefore, understanding the release behavior of LH2 is crucial for ensuring energy security and advancing hydrogen energy applications. This paper reviews the evolution of research on LH2 release behavior, highlighting key experimental and modeling studies. By combining bibliometric methods, the paper presents progress and trends from the micro level (specific research activities) to the macro level (statistical literature information). The Web of Science Core Collection was searched using keywords such as "liquid hydrogen" + "leakage," resulting in 571 relevant articles. After the manual screening, 349 valid articles were retained. The paper identifies a surge in research activity in recent years, particularly in countries such as China, the United States, and Japan. Despite this progress, there remains a lack of systematic studies and open-access data in certain areas. The paper also outlines advancements and trends in experimentation and modeling, which are crucial for the safe and effective use of LH2 in energy systems.