树冠火对输油站热辐射影响的数值模拟研究

Modeling and numerical study on thermal radiation to oil transport station by crown fire

树冠火是森林火灾的一种,在森林的树冠层燃烧和蔓延,主要由地表火在强风作用下引起。树冠火很少发生,约占森林火灾的5%,但其燃烧温度高、热释放速率大、蔓延速度快,对周围物体的破坏性极大。处在森林地区的输油站面临着树冠火带来的潜在风险。火灾产生的热辐射极有可能导致输油站内人员伤亡,设备遭到破坏。通过确定树冠火热释放速率、火灾发生位置及环境参数来设计火灾场景,采用火灾动力学场模拟软件FDS,模拟分析树冠火对输油站的热辐射影响。结果表明,由于无法采用地面扑救,防火隔离带是应对树冠火威胁的有效措施;当防火隔离带达到一定间距时,有风条件下与无风条件相比目标物体不会接收到更多的热辐射;防火隔离带设置为坡面形式,可以增加其表面积,从而吸收更多的热辐射。

Crown fire is one kind of forest fires,which burns and spreads through crown,and usually caused by ground surface fire with strong wind.Crown fire seldom occurs,which is about 5% the number of forest fires.But with high-temperature combustion,high heat release rate and fast spread speed,crown fire always brings great destruction to surroundings.Oil transport station in forest areas faces the potential risk of crown fire.Thermal radiation generated by crown fire is likely to make people dead and oil production facilities destroyed,causing serious economic losses.A fire scenario with crown fire scale,heat release rate,crown fire location and environmental parameters was designed using fire dynamics modeling software FDS as an analytical tool to conduct simulation analysis of the thermal radiation effect of crown fire.The results showed that because incapable of using fire fighting on the ground,fire barrier is one of most effective measures to prevent threat from crown fire.When the distance of fire barrier reaches a certain pitch,wind speed does not make object receive more thermal radiation.Fire barrier in a slope form,which increases surface area,can absorb more heat radiation.