Study On Engine Room Fire Simulation And Safe Evacuation Of A Bulk Carrier Based On Pyrosim And Pathfinder

As a place with high incidence of Marine fire,ship engine room not only has a narrow space,but also the environment will be greatly changed when a fire occurs.Factors such as high temperature and toxic gas will also greatly limit the escape movement of staff.Based on this background,this paper establishes the main research direction:fire simulation and safety evacuation analysis of ship engine room.In this paper,the engine room model to be analyzed is firstly established:there are four floors from the double bottom to the deck of an 82,000-ton cassam cargo ship.The simulation process of engine room fire is verified by numerical analysis in reference to a literature.Next,the model is used for the formal simulation of this paper,including three aspects:fire simulation,escape and evacuation,and optimization Suggestions.In terms of fire simulation,this paper determined three fire scenarios with different heat release rates of fire sources,and obtained the changes of temperature,human visibility,concentration ofCO₂ and CO concentration by simulating the combustion process of 900s time period after the ignition of fire source.And according to the human body bearing limit value of each parameter,the time when each parameter of the upper platform and the lower platform of the engine room reaches the limit value in different scenarios is determined.By comparing the shortest time as the available evacuation time（ASET）of different dangerous locations in this scene.In terms of escape evacuation,this article in different cabin allocate the sex workers,after the good human basic parameters for the process of fire and escape will be coupling calculation,get three scenarios staff retreat layers smoothly platform of dangerous position must evacuation time（RSET）,and by calculating the critical dangerous time to judge the risk of different space.At the same time,the results are used to observe whether there are people with life danger in the escape process,so as to evaluate the danger degree of the three fire scenarios.In terms of optimization Suggestions,this paper mainly improves the staircase with congestion.By changing the height of the stair,the width of the tread and the step ratio,the fire escape process was simulated again,and the staircase parameters with the shortest escape time were found.Finally,the staircase with the kick surface height of16cm and the step ratio of 2.2 is not only conducive to escape,but also greatly saves the internal space of the engine room,which can be used as an optimized staircase.In addition,according to the results of escape paths of each person in different fire scenarios,this paper also gives Suggestions on evacuation paths with the shortest time and the highest safety for the staff with different initial locations.