Diffusion evolution behaviour of flammable clouds by liquid hydrogen spills in confined space with force ventilation: A numerical investigation

Hydrogen, as a clean and carbon-free renewable energy with widespread applications, is a crucial medium for achieving substantial and deep decarbonization across various industries. This study employed a computational fluid dynamic (CFD) to investigate the evolution of liquid hydrogen diffusion spills in a ventilated garage. We validated our CFD model against experiments in a 39.96 m³ environment cabin equipped with an air supply and exhaust system. The model accurately simulates LH2 spills, revealing key insights into the behavior of diffuse clouds under different air supply velocities. Crucially, we observed that the separation distances of diffuse LH2 clouds were 0.29, 0.31, 0.87, and 1.03 m, and corresponding to unilateral air supply velocities of 0, 0.20, 0.60, and 1.00 m/s, respectively. Concurrently, cloud heights measured at 1.17, 1.90, 1.45, and 0.57 m revealed a complex interplay between ventilation dynamics and spill behavior. Our results indicate that increasing air supply velocity enhances the turbulent kinetic energy and dilution of the flammable cloud, while reducing its height and increasing ground-level risk. Additionally, higher supply air temperatures were associated with denser flammable clouds, featuring smaller separation distances and greater heights. These findings underscore the critical importance of optimized ventilation strategies in mitigating risks associated with LH2 spills in confined spaces.