Research On Numerical Simulation Of Air And Smoke Flow Characteristics In Subway Fire

As sealing property of it and large amount of property, fires in subway would causesevere lost and damage. Once fire occurred, smoke could be spread too quick to be diffusedand heating could rise rapidly. So study on smoke flow regularity and reasonable ventilationmode is taken to analyze condition of fire smoke spreading is important, temperaturedistribution and smoke concentration which is help to analysis fire scene, effective ventilationstrategies is chosen to calamity control and ensure the evacuation and fire rescue.A subway was taken as the research object in this paper, combustion characteristics atthe beginning of the combustion was analyzed, and the fire source was determined. A modelwas built according to its physical prototype, and then set the initial fire conditions and statusparameters. According to the basic conservation laws, a three-dimensional mathematicalmodel of fire smoke flow in tunnels was set up.Meanwhile, combined with subway structuredata, calculate evacuation time when fire in metro, as a reference evacuation time. Basis ongas product and propagation rule, the critical velocity was been calculated out when smokespreading. Based on theory of air compressor and computational fluid mechanics, super addthe national design code of subway, suitable ventilation modes was set up to this subwayaccording to its boundary conditions and fire spreading law. As the limitation of long-periodand complicated experiments, a simplified model were be taken in this paper for simulation.What’s more, a conclusion could be drawn by contrast of the fire products, temperature of fire,and heat release rate and concentration variation change with time in different ventilationpattern. Then the conclusion for the three different ventilation modes were analyzed andcompared, a suitable ventilation condition was chose for practical application in subway fireand provided reference for made emergency program of evacuation.