Speaker
Description
Hydrogen is increasingly recognized as an ideal clean energy source, with its use in industry proliferating. Among various storage and transportation methods, liquid hydrogen storage stands out for its high efficiency. However, the risk of accidental leaks leading to the formation of hydrogen clouds poses safety concerns due to hydrogen's high explosion potential and low ignition energy. Understanding and mitigating the consequences of such leaks is crucial for safely utilizing liquid hydrogen. To address this challenge, a research project has been carried out to develop a 3D numerical model by using the open-source computational fluid dynamics (CFD) code, OpenFOAM. This model aims to simulate the complex multiphase flow phenomena involved in the accidental leakage of liquid hydrogen, encompassing processes such as evaporation, condensation, heat exchange, diffusion, convection, multi-component, and radiation. The accuracy of the numerical simulations has been validated by comparing the results with experiments conducted by NASA.
An innovative approach known as the "air wall" has been proposed to enhance safety measures as an alternative to traditional fencing systems. The air wall consists of a series of upward air outlets placed to intercept the lateral diffusion of low-temperature, high-density hydrogen. These traditional walls could initially block the hydrogen. But as the temperature rises and the wind acts on it, the density of the hydrogen decreases, and the hydrogen climbs over the wall and continues to diffuse. The hydrogen moves to a certain distance on the ground along the wind direction until the density decreases significantly and the hydrogen leaves the ground. However, the air wall redirects the trajectory of hydrogen, increasing convection and diffusion rates and effectively reducing the hazardous range of hydrogen dispersion.
The protective efficacy of the air wall has been verified through numerical simulations. The geometric model is derived from modifications to the fencing design based on NASA experiments. The VOF multiphase flow model, the Lee evaporation condensation model, and the standard K-epsilon turbulence model have been used, and the details of other numerical models are described in the paper. Detailed descriptions of boundary conditions, settings, and simulation parameters are also provided in the paper. Comparative analysis between the traditional enclosure wall and the innovative air wall demonstrates significant differences in the trajectory of hydrogen dispersion. Employing the air wall results in substantially reduced lateral movement of hydrogen near the ground and increased vertical displacement compared to the enclosure wall. Overall, the findings suggest that the air wall offers a safer alternative for mitigating the consequences of liquid hydrogen leaks.
| Submitters Country | China |
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