The Simulation Study On Fire In Underground Intelligent Garage

China’s automobile ownership is growing rapidly,and it is also faced with problems such as parking difficulty and chaos parking.Underground intelligent garage with small footprint,more parking space,convenient access and other advantages have been a certain promotion.However,the underground intelligent garage fire with a large flue gas concentration,high fire temperature,evacuation difficulties and other characteristics,will endanger garage vehicles,garage structure,superstructure and so on.This article will refer to a large number of domestic and foreign automobile combustion experimental data.According to the relevant parameters of automobile component material,the automobile simulation model was established by using FDS software based on an underground intelligent garage constructed by reinforced concrete prefabricated.The numerical simulation of the ventilation and exhaust system of the underground intelligent garage and the automatic sprinkler system were carried out to an analyze the influence of the fire temperature of different fire scenes on the building structure.Give advice on ventilation exhaust from the underground garage intelligent use of the proposed safe and reliable water density and so on.The results of this study can provide reference for underground fire garage fire protection design and technology.The fire release rate(HRR),the flue gas flow,the fire area,the internal temperature of the garage,and so on were analyzed by the method of mechanical wind filling and natural smoke exhausting.The results show that when the mechanical wind is used,the effect of exhaust gas is better,but itleads to the acceleration of automobile combustion,the increase of internal temperature and surrounding temperature,and the increase of radiant heat.According to the radiant heat side point data,although not reach to the ignite conditions,but poses a serious threat to the adjacent vehicle.It is recommended that the fire be controlled or extinguished,and then open the garage import and export,and use the mechanical wind to smoke,but also pay attention to prevent the fire rekindle.Through the comparison and analysis of the simulation results of the fire release rate,the number of nozzle starts,the fire area and the internal temperature of the fire at different nozzles,the automatic sprinkler model of the underground intelligent garage is established.When the nozzle flow rate of 40L/min,the fire control effect is not ideal.When the nozzle flow reaches to 50L/min,60L/min,70L/min,80L/min,96L/min,the fire can be well controlled.With the increase of the nozzle flow rate,the heat release rate is reduced,the number of nozzle starts is reduced,the radiant heat is reduced,the interior temperature and the ambient temperature is decreased,the fire control reliability is higher and so on.From the fire area,economy and other comprehensive considerations,nozzle flow rate of 60L/min,70L/min can be a good meet the fire control requirements.Through the analysis of the temperature and temperature field near the structure of different fire scenes,according to the analysis of the temperature and temperature field near the structure of different fire scenes,and the characteristic curve of reinforced concrete in high temperature environment,when the mechanical wind is used,the temperature above the ignition vehicle reaches 1000 ℃,the duration of above 600 ℃ is 1170 s,the risk of deformation of garage structure is increased,thus,some fire protection measures should be taken.In other fire scenarios to garage structure has littleeffect,in short,intelligent underground garage mechanical air make-up should be measured.