| The rapid development of the world economy inevitably brings about great demand for energy.With the decrease of oil and gas resources on land,the development of Marine resources is an inevitable trend.As part of the ocean platform,the lower deck of the ocean platform carries the upper living area of the ocean platform.It contains a large number of atrium structures.In case of fire,the smoke will spread rapidly,threatening the control room,oil storage tank and other key areas.The smoke can be a threat to people's escape in a very short time.Therefore,it is very important to analyze the fire heat flow field of the lower deck and the evacuation of personnel.This paper mainly focuses on the fire field of the lower deck structure of the offshore platform.Using the method of large eddy simulation to study the spread and diffusion of fire smoke in main engine room and lower deck,and research the temperature,carbon monoxide concentration,oxygen concentration,visibility and other physical quantities of the main deck and the middle deck escape exits.And analyzing the factors that affect the evacuation of people and the results of the evacuation.By comparing and analyzing various fire scenarios and comparing with relevant safety standards,the safety evaluation is conducted.The calculated results are as follows:(1)Through the calculation and analysis of the characteristic parameters of the fire field in the main engine compartment,the fire broke into the overall development stage at 150 second,and the external combustion occurred after 200 second.At the same time,based on the temperature,concentration of carbon monoxide,visibility,oxygen concentration,critical analysis that visibility is the most dangerous fire characteristic parameters for interior personnel security in the main engine room,In the 80 second,visibility at the height of the human eye was rapidly reduced to 0m.The best escape exit is the back door of the cabin.(2)In this paper,the fire evolution characteristics of the lower deck of the ocean platform are analyzed.The influence of ventilation on fire development is analyzed.In both types of fire scenarios,there is an external combustion phenomenon,but the time of the fire scenario which have ventilation was delayed.It slows down the growth of temperature,carbon monoxide,and slows down the rate of decrease in visibility and oxygen concentration.At the same time,by comparing the fire source is located in the main engine room and mud pit agitator room fire scenario,found that when the position of the fire source changes,the port side of the lower deck of the ocean platform is more dangerous than the starboard side,and the entire port side is covered by the smoke at 160 second.(3)Calculate and analyze the temperature field of the lower deck at 1.6m height with and without ventilation in the main engine room.It can be seen that the temperature inside the main engine cabin is relatively high under the condition of no ventilation inside the engine room.However,under the condition of ventilation in the main engine cabin,the temperature of the surrounding cabin is low,indicating that the ventilation protects the structure of these cabins,but the damage to the interior of the main engine cabin is aggravated by the high temperature.(4)This paper analyzes the temperature,carbon monoxide concentration,visibility and oxygen concentration of the escape exits.This paper considers that visibility is the most dangerous parameter for people to escape from the exits.The two kinds of fire scenarios in the main engine compartment where have ventilation and don't have ventilation are compared and analyzed,it is found that ventilation can prolong the evacuation time of personnel.The conclusion of this paper can provide some reference and guidance for a building similar to the structure of the lower deck of the ocean platform on the analysis of fire field and the evacuation of personnel. |
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