隧道内障碍物对易燃液体蒸发爆炸的影响

Influence of Obstacles on the Vaporization and Explosion of Flammable Liquid in Tunnel

为分析隧道内易燃液体蒸发爆炸行为,使用VB.net作为集成开发环境对ICEM和Fluent进行二次开发,用户只需输入相关参数而不必关注具体计算模型,实现了网格划分和计算求解的自动化。使用该软件对隧道内障碍物是否存在两种情况下甲醇液池和庚烷液池蒸发后爆炸过程进行数值模拟分析。结果表明:无障碍物情况下,化学计量浓度下蒸气反应速率最快;有障碍物存在时,待流场达到稳定后,障碍物中间后方会出现没有蒸气的安全区域,安全区域两侧有蒸气存在。分子量较大的庚烷相对不易受到流场影响,其爆炸下限等值面较甲醇低,但其水平方向上危险区域更大。模拟设定情况下,两种蒸气爆炸产生的压力场相似,在爆炸初期均会形成一个球形压力波向外传播,其超压在2个大气压左右,两种蒸气爆炸均会对隧道内人员造成严重伤害甚至死亡。

In order to improve the efficiency of numerical simulation,ICEM and Fluent were secondary-developed using VB.net.Users only need to input relevant parameters without paying attention to the specific calculation model,which automates the mesh generation and calculation.The software was used to simulate the explosion of methanol and heptane pools in tunnel after evaporation with and without the obstacle.The results show that the vapor reaction rate at the stoichiometric concentration is the fastest without the obstacle.When obstacles exist,there will be a safety zone where no steam exists at a certain distance behind the obstacle center after the flow field reaches a steady state,and there will be steam on both sides of the safety zone.Heptane,whose molecular weight is higher,is less susceptible to flow field.Its isosurface of lower explosion limit is lower than that of methanol,but its dangerous area horizontally is larger.The pressure field of methanol vapor and heptane vapor explosion is similar.In the early stage of explosion,a spherical pressure wave propagates outwards,and its intensity is about 2 bars.Both kinds of vapor explosions can cause serious injury or even death to personnel in tunnels.