大跨建筑屋面形体对火灾烟气流动的影响研究

Study on the influence of large-span building roof shape on fire smoke flow

大跨度建筑屋面具有丰富的形体,这种屋面形状的变化将在很大程度上影响体育馆发生火灾时内部的烟气流动特性,进而对防火安全、人员疏散产生影响;同时,研究屋面形状对烟气流动的影响也是合理设置屋面通风口的基础。首先建立了平屋顶、椭球面屋顶、球面屋顶、马鞍面屋顶大跨建筑模型,然后利用Pyrosim软件以圆柱面屋顶体育馆为典型情况分析了在火灾发生时建筑内的烟气流动、能见度、温度、一氧化碳浓度等各项关键指标;在此基础上对5种屋面形体的规律差异及火灾情况的影响情况进行了归纳分析,获得了屋面形状对火灾时场馆内烟气流动情况的影响规律。分析结果表明:不同的屋面形状对应的烟雾蔓延情况有较大差距,但经过比较分析屋面较为隆起的球屋面较有利于消防和人员的疏散;对于圆柱形屋面体育馆,相比于观众区较慢爬升的温度,烟雾所造成的能见度的降低对人员逃生的影响更加显著。

The large-span building roof has a rich shape and the change of the roof shape will greatly affect the internal smoke flow characteristics in the fire in the stadium,which will affect the fire safety and personnel evacuation.At the same time,studying the influence of roof shape on the flow of smoke is also the basis for rationally setting roof vents.First,a large-span building model of flat roof,ellipsoidal roof,spherical roof and saddle roof was established.Then,the cylindrical roof stadium was used as a typical case to analyze the smoke flow,visibility,temperature,and CO concentration by using the Pyrosim software.On the basis of this,the regularity differences of five roof shapes and the impact of fire conditions were summarized and analyzed,and the influence of roof shape on the flow of smoke in the stadium during fire was obtained.The result shows that different roof shapes correspond to large differences in smoke spread,but after comparison and analysis,the spherical roof in a relatively high level is more conducive in terms of firefighting and personnel evacuation.As for a stadium with a cylindrical roof,the decrease of visibility caused by smoke have a more significant impact on the escape of personnel than the temperature factor which rises slowly in the audience area.