典型多层经营性自建房火灾初期处置效能的大涡模拟

Large eddy simulation on multi-story commercial self-built residential fire's initial battle effectiveness

针对多层经营性自建房建筑结构及火灾荷载特点构建典型建筑全尺寸模型,进行火灾动力学模拟分析及拓展研究,以提高火灾初期处置效能。设置系列火灾模拟场景输出表征项,采用雷达图等方式量化对比不同初期处置战术措施效能。结果表明,自建住宅因多层、内设楼梯井等建筑结构特点,火灾过程中热烟气易在楼梯井、采光井等结构内大量蓄积。在建筑二层或以上空间有人员被困的火场,二层出水冷却、破拆顶窗联用出水等2种战术措施能够在短时间内迅速降低二层及以上空间温度及烟气浓度;对一层火势控制作用虽不明显,但反作用影响亦不大。一层出水冷却虽可对一层火势形成有效控制,但易驱赶、加剧热烟气向上层流动扩散,有人员被困时不利于内攻搜救。二层排烟、破拆顶窗等2种战术措施用于一层火灾荷载较大、二层以上空间已有大量热烟气聚集的火场,易引发回燃,应谨慎使用。涉及出枪射水的战术措施,建议应尽量选用能够形成较小粒径液滴的灭火器具,在压制火场火势降温、吸附烟气粒子降毒方面可取得较好效果。

This study takes multi-storey commercial self-built residential fire's initial battle effectiveness as the object,and builds full-scale models of typical buildings for fire dynamics simulation based on the structural characteristics and fire load of self-built residential buildings,which focuses on the"1·31"self-built residential fire disposal case in Hechi,Guangxi.It sets up a series of fire scenes to simulate,and the effectiveness of different initial battle disposal tactical measures is quantified and compared using a radar chart.The results show that the simulation can restore the initial disposal of the"1.31"fire in Hechi,Guangxi,and fire behavior characteristics described by the calculation results are roughly consistent with the relevant time nodes and phenomena on site.Hot flue gas is easy to accumulate in the stairwell,day-lighting well in the fire.In a fire site where people are trapped in a space of 2F or above the building,water squirting and breaking down the window combination can quickly reduce the temperature and smoke concentration in the space of 2F or above in a short time;Although the control effect on the first-floor fire is not obvious,the reaction effect is also small.1F water squirting can effectively control the fire of 1F.It is easy to drive and aggravate the flow and diffusion of hot flue gas to the upper layer,which is not conducive to creating favorable internal attack search and rescue conditions when some people are trapped.2F smoke exhausting and air supplying,dismantling the ventilation window on the top floor ceiling are used in the fire site with large fire load on 1F and a large amount of hot smoke has accumulated in the space above 2F,which is easy to cause back combustion and cause great harm to trapped and internal rescue personnel,so they cannot be used blindly.For tactical measures involving water squirting,fire extinguishers that can form small particle-size droplets should be selected as far as possible,which can achieve good results in reducing temperature and poison at the fire site.