NUMERICAL STUDY OF INSULATION PRESSURE AND STRUCTURE EFFECT ON VAPOR-COOLED SHIELD PERFORMANCE

Abstract

Hydrogen energy, recognized as a clean, green, and efficient energy source, has garnered significant global attention and has seen considerable development in recent decades. However, storing hydrogen energy has posed a significant obstacle to its progression. Due to its high energy density, liquid hydrogen stands out as an exceptionally efficient hydrogen storage method relative to other methods. The notably low liquefaction temperature of hydrogen necessitates superior thermal insulation performance for liquid hydrogen storage tanks. The vapor-cooled shield (VCS) is a highly effective long-term liquid hydrogen storage insulation method. The VCS utilizes cryogenic vapor, which evaporates from the tank, to cool the insulation layer, thereby diminishing the heat intrusion into the storage tank. This research delves into the correlation between the VCS's structure and thermal insulation performance, establishing three-dimensional VCS models varying in tube diameters and numbers. As the diameter and number of VCS tubes augment, the interface area between the VCS tubes and the VCS shield also expands, enhancing the VCS's thermal insulation performance. Based on our findings, under the 10-5 Pa insulation pressure condition, the heat intrusion is curtailed to 0.159 W/m2 for the 8-tube, 12 mm model, a significant drop from the 0.469 W/m2 observed in the model devoid of VCS ― a reduction of 66.16 %. Even the 4-tube, 4 mm model, the least efficient among the models studied, records a heat intrusion of 0.324 W/m2, marking a 30.9 % reduction compared to the model without VCS. These outcomes underscore the VCS's pronounced enhancement in the insulation layer's effectiveness, emphasizing that the insulation's performance is intricately linked to the VCS's structure.