Numerical study on the leakage characteristic of the damaged LNG carrier in different wind scenarios

Leakage accidents on an LNG (Liquefied Natural Gas) carrier pose a significant threat to the safety of ship's structures and rescue personnel. This paper proposes a numerical approach by combining CFD (Computational Fluid Dynamics) and VOF (Volume of Fluid) boiling modules. This approach simulates the RPT (Rapid Phase Transition) behavior of cryogenic liquid cargo and dynamically visualizes the density field, temperature field, and diffusion range of the phase transition gas in the leakage process. Numerical convergence is verified based on the mesh and time-step sensitivity analysis conducted in the no-wind condition. Four additional scenarios including two beam wind directions, head wind, and following winds are applied to investigate effects of wind direction on the leakage characteristics. From the perspective of rescue management and disaster prevention, beam winds towards the damaged side represent the most dangerous scenarios, high methane concentration around the hull would increase the explosion risk while large cryogenic diffusion would reduce the safety of cargo tanks. Therefore, it is necessary to adjust the relative direction of the damaged LNG carrier to avoid being in this wind direction. Moreover, considering the safety of emergency personnel, the operation region should be positioned in the upwind area.