燃气泄漏过程及爆炸对建筑构件损毁的数值模拟研究

近年来,由燃气泄漏引起的爆炸事故逐渐成为人们关注的重点。为探究燃气泄漏规律以及其爆炸对建筑物损毁效应,采用计算流体动力学分别模拟了燃气在密闭空间和开放空间的泄漏扩散,同时运用Autodyn软件的Remap技术模拟了密闭空间的三种墙壁在燃气爆炸作用下的损毁过程,研究了墙壁水平和竖直方向的压力、速度以及位移变化规律。结果表明:燃气在密闭空间的扩散速度小于在开放空间的扩散速度;两种空间的燃气泄漏口处观察点在0～15 s时的质量分数变化趋势一致,15 s后密闭空间的质量分数继续增加,而开放空间的质量分数基本保持不变;砖墙、钢筋混凝土墙和混凝土墙的位移时程曲线皆表现为线性变化;三种墙壁的压力峰值、速度峰值以及位移峰值随距离增大多表现为指数衰减趋势;相同距离下,砖墙的压力峰值、速度峰值和位移峰值在水平、竖直方向的差值大于其余两种墙壁的差值。

Numerical simulation of gas leakage process and damage of building components caused by gas explosion

In recent years, the accidents caused by the explosion via gas leakage have gradually become the focus of attention. In order to explore the law of gas leakage and the damage effect of the explosion on the building, CFD (Computational Fluid Dynamics) was used to simulate the gas leakage law in confined space and open space, respectively. Simultaneously, the Remap technique of software AUTODYN was applied to simulate the damage process of three kinds of walls, and the change rules of the pressure, velocity and displacement of walls in horizontal and vertical direction were investigated. The results show that the diffusion velocity of the gas in confined space is less than that in open space. The change trends of the mass fraction of observation points at the gas leakage hole in 0-15 s keep consistent in the two spaces. The gas mass fraction in confined space continues to increase after 15 s, while in open space the mass fraction basically keeps unchanged. The displacement-time curves of the brick wall, the reinforced concrete wall and the concrete wall present linear change. The pressure peak, velocity peak and displacement peak of the three kinds of walls show exponential decay with the increase of the distance. At the same distance, the differences of pressure peak, velocity peak and displacement peak of the brick wall in the horizontal and the vertical direction are greater than the differences of the other two walls.