Abstract:

Using methane as a representative gas, the effects of different hole types and different sizes of perforated obstacles on the explosive flame and pressure propagation of combustible gas were studied in a closed conduit of 10% methane. The study found that when the obstacle partition is set, the explosion overpressure slowly grows in front of the obstacle, and continues to increase by the obstacle, and rapidly decreases before reaching the blind plate. The flame propagation rate increases slowly first and falls before passing through the obstacle partition, and rises sharply to the maximum after passing through the opening. As the opening area of the obstacle partition is reduced, the jetting effect caused by the airflow is obviously enhanced, and the influence caused by the negative pressure suction is increased, which leads to a more uneven distribution of the overpressure before and after the obstacle, and the obstacle is separated. The flame propagation speed in front of the plate decreases. Under the same opening area, the maximum overpressure and flame propagation speed are affected by different hole types. When the flame passes through the perforated obstacle partition, the circular opening is more in line with the flame shape than the square opening and the regular triangular opening. The law of development, the inner circular hole is smaller than the square hole, the flame is more affected, the turbulence is more obvious, and the flame speed and pressure rise are more obvious. The maximum overpressure relationship of different hole types is P _triangle>P _square>P _round>P _empty, flame propagation speed relationship is v _triangle>v _square>v _round>v _empty.

Key words: explosions, methane, flame propagation speed, overpressure, obstacle, kinetics

摘要：

以甲烷为代表性气体，研究了在10%浓度甲烷的闭口管道中设置不同孔型、不同尺寸的带孔障碍物对可燃气体爆炸火焰和压力传播的影响。研究发现：设置障碍物隔板时，爆炸超压在穿过障碍物前缓慢增长，并受障碍物影响继续增大，在到达盲板前快速降低。火焰传播速度先缓慢增加，并在通过障碍物隔板前下降，在穿过开孔后急剧上升至最大值。随着障碍物隔板的开孔面积减小，其造成的气流喷射作用会明显增强，负压抽吸作用造成的影响增大，会导致障碍物前后超压分布更加不均匀，在障碍物隔板前的火焰传播速度下降幅度增加。同阻塞率条件下，最大超压和火焰传播速度均受到不同孔型的影响，火焰在穿过带孔障碍物隔板时，圆形开孔相对方形开孔和正三角形开孔更符合火焰球形发展规律，正三角形孔内切圆比方形孔小，火焰受到的影响更大，湍流更加明显，导致火焰速度和压力上升更加明显。不同孔型的最大超压关系为P _三角孔>P _方孔>P _圆孔>P _空载管道，火焰传播速度关系为v _三角孔>v _方孔>v _圆孔>v _空载管道。

关键词: 爆炸, 甲烷, 火焰传播速度, 超压, 障碍物, 动力学