Speaker
Description
Safe, compact, lightweight, and cost-effective hydrogen storage technology is key to the comprehensive development of hydrogen energy. Cryo-compressed hydrogen storage refers to the use of adiabatic, pressure-resistant vessels to store hydrogen in a supercritical state under the cryogenic temperature and high-pressure. Compared with other hydrogen storage methods, it has significant advantages in terms of hydrogen storage density, storage cost, safety, and non-destructive storage time. However, the two extreme conditions of cryogenic temperature and high pressure impose high demands on the performance of hydrogen storage vessels. As the main ultimate bearing parts of vessels, the composite material layer generates stress concentration phenomenon under cryogenic temperature and high pressure. This leads to damage such as fiber fractures, matrix microcracks, and fiber-matrix debonding, affecting the ultimate bearing capacity and fatigue life of the vessels. In order to ensure the safety of hydrogen storage vessels under cryogenic temperature, it is necessary to study its cryogenic mechanical properties and optimize structure.
For the mechanical properties of cryo-compressed hydrogen storage vessels, the composite winding layer is designed based on the grid theory. Numerical simulation to analyze the stress distribution of the metallic liner and the winding layer under operating conditions. The maximum stress criterion is used to determine the ultimate bearing capacity of the vessels. The effects of winding angle, autofrettage pressure and stacking sequence on the cryogenic mechanical properties and fatigue life of the vessel are further investigated, and the results are used in the optimization of the vessel structure. The study focuses on a vessel with a volume of 20 liters, operating at 20 MPa and 80K. The results show that the stress level of the hoop winding layer increases by at least 90% compared with that of the helical winding layer, and the stress is uniformly distributed in the cylinder section, with a decreasing trend near the head. When the winding angle increases, the maximum stress at the cylinder section of the winding layer decreases, while the maximum stress at the head section first decreases and then increases. When the autofrettage pressure is increased from 29 MPa to 37 MPa, the average stress of the metal liner at working pressure decreases by 43.2%, which is conducive to increasing its fatigue life. Instead of concentrating all the hoop winding layers in the inner or outer of the layers, alternating between hoop winding and helical winding is more favorable to improve the comprehensive performance of the composite. Further, based on the results of each sub-study, the structural design and optimization of vessels is supported.
| Submitters Country | China |
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