Natural gas diffusion behavior and gas detector layout in the ship engine room considering heat radiation effect

LNG (liquefied natural gas) has been regarded as one of the most practicable and promising clean energies for ship power systems. However, the LNG-powered ships may take high risk of fire and explosion accidents due to natural gas (NG) leakage. The diffusion behaviors of the NG are often influenced by the heat radiation in the engine rooms. This study looks into the mechanisms of the heat radiation effect on the NG diffusion. Experimental study and numerical simulations were conducted to verify the effect of heat radiation on NG diffusion within the engine room. The mechanism by which heat radiation impacts NG diffusion was explored using a validated gray band radiation model. A hazardous gas assessment model was developed to quantify the dynamic diffusion of NG. Results indicate that the gray band radiation model more accurately replicates the temperature field. Compared to the non-radiation model, the gray band radiation model shows an 18.95% higher volume of NG with a 1% concentration. Based on the concentration distribution of NG under various working conditions, an optimized gas detector layout was proposed. The finding provides a reference for monitoring radiative gas diffusion in thermal environments and detecting NG leakage in LNG-powered ship engine rooms.