In this paper, the Fire Dynamics Simulator code is used to study the fire within the engine room. The 3D numerical model with multilayer structure and multiple subregions is proposed to represent a real ship engine room structure. This model has many special characteristics compared with the monolayer structure; the whole space is separated into many multilayer structures and multiple subregions. And many valuable results are obtained.
(a) It is generally agreed that the large eddy method is accurate in 3D reconstructing the fire in ship engine room with multilayer structure. And it is an economical and valid method compared with the experimental method.
(b) The multilayer structure not only may enhance the combustion intensity and induce the formation of the ceiling jet, but also may enhance the thermal flow transport within each zone in the engine room, can effectively prevent the firing and control its developing.
(c) There is great temperature gradient within the engine room at the place far away from the fire source; the local temperature increases more slowly than the fire source point. Thus, the worker can control the fire by using a fire extinguisher in the early stage. Additionally, the local oxygen concentration has great effects on the temperature. Especially, at the later stage of the fire developing, the change of the temperature is proportional to the oxygen concentration
(d) During the fire developing, there is a large pressure difference between the engine room and the environment. And the leak of the oxygen may reignite the fuel. Then a strict sealing is required for the ship engine room design.
(e) In this paper, we can know the distribution characteristic of the fire field in a ship engineer room with multilayer structure. In the next step of research and practical application, using a new method to effectively reduce the smoke concentration in an enclosed engineer room may be significant for the ship fire fighting.