Numerical Study on Diffusion Law and Risk Assessment of Indoor Hydrogen Leakage

Abstract Energy shortages and environment pollution are among the most important problems all over the world. As a clean and renewable energy carrier, hydrogen is expected to be one of the most promising alternative solutions to the energy and environmental problems in the near future. However, the safety issues in hydrogen production, transport and storage have to be thoroughly addressed before commercialization of hydrogen energy to give authorities confidence and to eliminate the public fear of using hydrogen. Accurate knowledge of the dispersion characteristics of unintended hydrogen releases in the atmosphere is essential to developing good standards and codes for hydrogen safety. This paper presents a numerical study on the indoor hydrogen leakage risk assessment and numerical simulation. The physical and mathematical model of hydrogen leakage and diffusion process are established. Based on computational fluid dynamics, the numerical simulation of hydrogen leakage process is studied. The effects of leakage source height and direction on hydrogen leakage and diffusion in indoor space are analyzed. The results show that the hydrogen leakage in the laboratory space is initially diffused by jet. With the development of time, the leaked hydrogen with different height and direction of leakage source forms different forms of vortex in the space, which affects the speed and amount of hydrogen accumulation in the space. When the hydrogen leakage source is low, the leakage direction is downward and back to the vent, the safety risk is greater.