局部扰动对主坑道爆炸波发展的数值模拟与实验研究

Experimental and numerical simulated study of explosive waves expansion by local disturbance in main tunnel

在地下建筑物,如隧道、地下储油库、人防工程、地下物资仓库等里面,由主通道旁结分支通道是最常见的一种布置形式,是一种典型的复杂受限空间结构。一旦有可燃气体发生爆炸燃烧,爆炸压力波和火焰的传播将受众多因素的影响,其中局部扰动的影响是主要因素之一。本文通过实验和数值模拟的方法研究了油气混合物在该复杂受限空间中由弱点火引起爆炸燃烧的发展过程,湍流强度经旁接分支坑道后在主通道中的变化,以及爆炸压力波和火焰经局部扰动后的变化过程;并将数值模拟结果与实验结果进行了对比和综合分析,得到了与地下受限空间安全相关的重要结论。湍流强度是复杂受限空间中可燃气体爆炸燃烧发展过程的主要影响因素之一,局部扰动将增强爆炸流场的湍流强度,加速燃烧化学反应,能量的释放量和速率大大提高。这些能量的快速加入促进了高峰值压力波的形成,火焰也被加速,爆炸从此由弱转强,出现跃升。研究结果对地下受限空间爆炸过程的进一步研究以及爆炸灾害的预防都有参考价值。

This paper aims to present the author＇s work on an experimental and numerical simulation of the explosive wave expansion triggered by weak ignition in the complicated confined space. The paper also deals with the change of the turbulence intensity in the main tunnel after passing through the branching tunnel, and the expanding process of the explosion pressure wave and flame caused by the local disturbance. Analyzing and comparing the value of the numerical simulation with that of the experiment, we have reached an important conclusion that is related to the safety of the underground confined space safety. That is to say, the turbulence intensity is one of the key influential factors leading to the explosive combustion development of the fuel-air mixture in the underground complicated confined space. At the same time, the local disturbance is likely to enhance the turbulence intensity of explosion, accelerate the chemical combustion reaction, add the value and the rate of the energy liberation and eventually lead to strong explosion and pressure wave transition. Thus, it can be seen that the conclusion gained in this paper may have important reference values to the further studies on the explosion process and the explosion prevention. In the underground architectures, such as tunnel, underground fuel depot, civil defense, material warehouse and so on, it is a common arrangement that the branch tunnel is connected with its main tunnel as a kind of typical complicated confined space structure. Once combustible gas is ignited, which leads to explosion, the explosion pressure wave and propagation of flame will be influenced by many more factors. Among them the influence of local disturbance is one of the main factors.