Hydrogen diffusion characteristics and ventilation verification in a marine engine room

This article explores the hydrogen diffusion behavior through multi-factor coupling, and based on the design standards of ship ventilation, calculates and verifies the safe ventilation volume in the engine room. The results indicate that during the initial stage of leakage (t ≤ 58 s), low-speed ventilation (u ≤ 4 m/s) will promote hydrogen diffusion; as ventilation continues, a larger ventilation speed can discharge hydrogen from the engine room. The equipment operating condition doesn't have a significant impact on the hydrogen hazardous area volume, but it should be noted that high-temperature areas are prone to hydrogen accumulation. Raising the humidity to 80 % will reduce the hydrogen jet's momentum, while recommended levels are 40 %–60 % for stable hazardous area control. The hydrogen diffusion and hazardous area increase significantly with the increase of leakage pressure. So, the higher the leakage pressure, the higher the risk of hydrogen leakage. Numerical simulation verification shows that a ventilation speed of 9.3 m/s can maintain a suitable working environment, and when hydrogen leaks, the ventilation speed needs to be increased to 18.6 m/s to ensure engine room safety. The research results can provide data support for the safety regulations and accident prevention of hydrogen-powered ships.