数值仿真技术在受限空间气体爆炸案件现场勘查中的应用

Numerical Simulation Investigating into the Crime Scene of Spaceconfi ned Gas Explosion

目的确定民宅类受限空间气体爆炸案件的起爆位置。方法运用FLACS软件对某居民楼因液化石油气泄放引发的气体爆炸过程进行数值仿真研究,选取可疑起爆区域内的两处起爆位置,即某卧室床南侧中部A点与床北侧对称位置B点,分析两点产生的爆炸冲击波对木门、床垫的作用与现场木门、床垫位移情况的吻合程度,确定起爆位置所处区域。结果A点与B点起爆产生的爆炸冲击波对木门的作用与现场木门位移情况吻合,只有A点起爆产生的爆炸冲击波对床垫的作用与现场床垫位移情况吻合,因此起爆位置位于A点所在的床南侧区域,经现场分析推断点火源为南墙上的电灯开关。结论FLACS软件可对受限空间气体爆炸案事件过程进行模拟,为现场痕迹特征分析、关键物证认定等提供了有力支撑。

Objective To determine the ignition site in the crime scene of space-confined gas explosion.Methods FLACS,one software,was adopted to numerically simulate the gas explosion caused from liquefied petroleum gas releasing in a residential building,with the suspicious scene ignition sites of A and B being analyzed into the effect of explosive shock wave on the involved wooden door and mattress.Site A was selected at the middle of the south side of a bed in one bedroom,with site B being symmetric to A in the north side of the bed.The results from numerical simulation were verified with the actual displacement of the blown wooden door and mattress,thereby having the ignition site determined.Results The simulated explosion shock wave,generated from the site either A or B,caused the identical displacement of the wooden door as shown with the scene fact,yet only the site A resulting in the same displacement of the mattress as shown on the scene from the shock wave generated there.Thus,the ignition site was determined at site A.Further scene investigation and analysis confirmed that the ignition source is the light switch on the wall at the south beside the bed.Conclusions FLACS can simulate the process of gas explosion event in a building,capable of providing strong support for feature analysis of scene traces and identification of key material evidence.