小尺度受限空间内瓦斯爆燃的动态特性

Dynamic Characteristics of Gas Deflagration in Small-Scale Confined Space

为获得包括瓦斯爆燃点火初期、火焰加速、减速及二次加速过程中动态火焰微细结构及其与超压之间的相互关系,实验研究了小尺度受限空间内瓦斯爆燃火焰形状、火焰锋面位置、火焰速度及超压等动态特性.研究结果表明,在无障碍物条件下,火焰锋面光滑,火焰形状由"半球"状逐渐演变为"手指"状;而有障碍物条件下,火焰锋面出现明显褶皱和湍流现象,其火焰速度经历两次加速和一次减速过程,最大火焰速度达112m/s,与无障碍物条件下最大值相比增幅为124%;当火焰锋面经过障碍物后即将重新汇合时,出现8.5kPa的最大超压,与无障碍物条件下的最大值相比增幅为118%.

To obtain the micro-structure of dynamic flame and the relationship between propagating flame and over- pressure in the gas deflagration process, including initial ignition, flame acceleration, deceleration and second ac- celeration, an experimental study on the dynamic characteristics of gas deflagration in a small-scale confined space, such as deflagrating flame shape, flame front position, flame speed and overpressure, was carried out. The results show that the flame front is smooth and the flame structure gradually develops into a finger-like shape from hemi- sphere if there is no obstruction. However, if there is an obstacle, the flame front is distorted and turbulent. As a result, the flame speed experiences two accelerations and one deceleration. The maximal flame speed is 112 m/s which is increased by 124% compared with that without obstacle. When the flame front is going to be reconnected immediately after having crossed over the obstacle, the peak overpressure occurs, which is 8.5 kPa, increased by 118%.