Numerical Simulation Of High-pressure Water Mist Fire Extinguishing System In Underground Garage

With the rapid development of social economy in our country,people’s living standards have been greatly improved.More driving and less walking are now becoming the mainstream of people’s travel mode,and thus a majority of urban building facilities are now equipped with large-scale underground parking lots.At present,the automatic sprinkler system is one of the most widely-used fire extinguishing facilities.Based on the use of such a system in fire cases in various buildings,there exists such problems as large water consumption,high chance of giving rise to splashing of boiling oil and fire,in-applicability to some special areas(like the electrical equipment room).In order to solve these problems,we need to study and explore a brand-new and energy-saving water-based fire extinguishing system — the high-pressure water mist fire extinguishing system.This paper tries to use fire dynamics software to simulate the working conditions of fire scenes in an underground parking lot to study the fire extinguishing effects of the high-pressure water mist system.The main research way of this paper is to use FDS software to create a full size model of underground garage,and to design 4 different working conditions combined with the practical application of the project,and then use Pyrosim program to simulate it,and then compare and analyze the results of different working conditions to draw a conclusion.The research steps are: first,based on the characteristic parameters of the high pressure fine water mist and the influence factors of the fire extinguishing effect,and referring to the actual fire-fighting measures selected in the underground garage,a targeted fire scene simulation scheme is formulated.Secondly,the full dimension three-dimensional model is established by using the FDS software,and the fire scene is set not in the designed fire scene.The same fire protection measures are simulated.Finally,by analyzing the change of fire parameters such as fire field heat radiation,smoke flow and carbon monoxide concentration,the results of different fire prevention measures are compared.The simulation results show that:1.When the high pressure water mist system is independent,it can effectively suppress the heat radiation to reduce the temperature of the fire field,and finally extinguish the firesource.At the same time,it can also improve the visibility of the flue gas and reduce the carbon monoxide concentration,and the effect of fire extinguishing is better.2.When the high pressure water mist and mechanical smoke exhaust joint role: in the process of fire,the mechanical smoke extraction can be dispersed around the fire,high temperature flue gas fire quickly reduce the temperature,improve the efficiency of fire extinguishing,the flue gas has a certain visibility to ascend,but relatively little change carbon monoxide concentrations.3.Through quantitative comparison with water spray system is: from the Angle of fire suppression in the process of fire,the effect of high pressure water mist in extinguishing reflect a certain advantage,but the dilution effects of high pressure water mist for carbon monoxide is relatively weak;From the point of view of the total water consumption required for fire fighting,the water consumption of high pressure water mist during fire fighting is only about 1/6 of that of water spraying.