Accident Consequences Simulates In Three-Dimensional And Prediction Of LNG Fueled Ship

The using of LNG as a ship fuel gas can reduce the emission of pollution and greenhouse gas effectively, its social and economic beneficial results are obvious, but the research on the LNG fueled ship is in the blank stage. In this paper, using FLACS commercial software as a tool to research and simulate a simple model of leakage and diffusion influence, and the analysis of NG cloud explosion under different conditions. On this basis, using the preprocessor CASD of FLACS to build a three-dimensional physical model according to a LNG fueled ship’s actual size of a company in Wuhu, Anhui, which tests successfully and using k-ε two-equation model to solve the turbulence problem, and do the numerical simulation of the LNG in two-phase, and based on the leakage and diffusion, according to the calculation principle of fuel mass fraction transport equation, simulate the explosion of clouds. The main results are as follow:(1)With or without obstacle influence the forming of the pool in the LNG simple diffusion, the radius with obstacle is longer than without, the obstacle has a obstruction in the vapor diffusion, and the radius of the vapor diffusion is smaller than the scenarios without obstacle, on the opposite, the cloud width is greater than the latter;(2)The consequences of the LNG gas cloud explosion is affected by the three-dimensional physical model’s rate of internal blocking and the space constraints, the higher the rate of internal blocking and the more of the space constraints, the higher of the overpressure shockwave’s peak, and the faster of the propagation velocity, external obstacles will affect the formation of the overpressure shockwave, the overpressure shockwave’ peak will cut down quickly, we can design blast walls according to the waveform graphic in practice;(3) The final form of pools don’t change in the three different leakage and diffusion scenarios of the LNG fueled ship, Wind direction have no effect on the formation of pools. Different scenarios have an effect on the forming of the gas clouds, the simulation results indicates that the position of the clouds’ maximum height in the forming process is in the lower side of the tank. The width of the clouds is nearly the same of the three scenarios, heavy gas clouds are concentrated on the main deck, and unroll along the deck in the aft, the position of the clouds’ maximum height in the forming process is in lower side of the tank. Changing the source of the leakage location and direction of the wind do a slight impact of the vapor diffusion in the LNG fueled ship, its highest concentration region’location is above the pool, the simulation results indicate that the maximum radius of the combustible area is coming from scenario one,17.23m;(4)LNG fueled ship takes place two explosions and forms two pressure waves, the maximum explosion overpressure is distributed inside the second floor deck, We can predict that the radius of the LNG fueled ship’s four kinds of damage level were37.53m,28.51m,23.82and9.13m.