Experimental Study On Evolvement Of Fire And Smoke Control In Long And Narrow Space

In long and narrow space,room is sealed,thus when fire disaster happens,air circulates smoothly in the vertical.High temperature spreads rapidly,gas and smoke particles produced by incomplete combustion increase significantly,hyperthermal smoke cannot be discharged,and accumulation of heat is aggravated.All these factors contribute to faster fire spread,and consequently the danger and difficulty of rescue is increased.Massive injury and death can easily happen,resulting in heavy casualties and property losses.Therefore,it is essential for studies in fire extinguishing and emergency rescue in the long and narrow space fire to research on its course of evolution.A smallsized long and narrow space experiment model(length*width*height is 3.6m*1.5m*0.6m)was set up in this paper.In the experiments,By changing the main fuel's kinds,location and quantity of the opening,wind velocity in the crosssection,and forces inflicted by water mist.,has carried out a series of indentation size fire experiment.The development process of fire disaster with various fuels under two opening condition is studied.It turns out that the character of burnable liquid fuel influences fire's growth and spread significantly.In the circumstance that is described in this article,when fire grows,the fire fueled by diesel discharges,while that fueled by alcohol does not.In terms of different characters of combustion sources,the feasibility of measuring threshold for flashover stands higher when using ground to receive heat radiations.No matter the fire is fueled by diesel or alcohol,if the fire source is in the middle of a limited space,fire smoke will spread vertically from the center of the source.On the two sides of the fire source,the smoke is in a axisymmetric distribute.Both the two sides can be divided into flame and heated smoke zones.Horizontally,according to the temperature of fire smoke,the pool fueled by diesel can be divided into upper and bottom smoke zones while the pool fueled by alcohol can be divided into upper,middle,and bottom smoke zones.Then,the experiments shows that increasing the ventilation area,flue gas loss is enhenced,which burning is also strengthened.The experiments also prove that by increasing amount of smoke exhaust,the fire temperature in long and narrow space,the radiation received by the ground,and the density of O2 and CO in flue smoke layers are all affected obviously.In natural ventilation with two openings,Lit the oil pan 8 min after the start water mist,the experimental results shows that,for sprayhead with k=1,after providing water mist with 3Mpa force,the burning time of the fire source extends and the fire is aggravated.When the force increases to 7Mpa,the temperature of flame drops dramatically and the fire is extinguished effectively.Water gas reaction happens between water mist and rubber in fire space and hydrogen is created,which strengthens the burning.The density of hydrogen around rubber decreases when the force on water mist increases.The result of the experiments illustrates that the major mechanism of using water mist to extinguish fire fueled by alcohol is water mist's cooling effect,distinguishing fire fueled by alcohol and the attenuation of radiant heat.