The effect of internal shape of obstacles on the deflagration of premixed methane–air (concentration of 10%) was experimentally investigated in a semi-confined steel pipeline (with a square cross section size of 80 mm × 80 mm and 4 m long). The obstacles used in this study were circular, square, triangular and gear-shaped (4-teeth, 6-teeth and 8-teeth) orifice plates with a blockage ratio of 75%, and the perimeter of the orifice was regarded as a criterion for determining the sharpness of the orifice plate. The overpressure history, flame intensity histories, flame front propagation speed, maximum flame intensity and peak explosion overpressure were analyzed. The explosion in the pipeline can be divided into two stages: initial explosion and secondary explosion. The secondary explosion is caused by recoiled flame. The perimeter is positively related to the intensity of the recoiled flame and the ability of orifice plate to suppress the explosion propagation. In addition, the increase in the perimeter will cause the acceleration of the flame passing through the orifice plate, while after the perimeter of the orifice reaches a certain value, the effect of the increase in perimeter on explosion excitation becomes no obvious. The overpressure (static pressure) downstream of the orifice plate is the result of the combined effect of explosion intensity and turbulence. The increase in perimeter leads to the increase in turbulence downstream of the orifice plate which in turn causes more explosion pressure to be converted into dynamic pressure.

在半封闭式钢管（方形截面尺寸为80 mm×80 mm，长4 m）中，通过实验研究了障碍物内部形状对甲烷（空气混合气）爆燃（浓度为10％）的影响。本研究中使用的障碍物是圆形，正方形，三角形和齿轮形（4齿，6齿和8齿）孔板，其堵塞率为75％，孔的周长被视为标准用于确定孔板的清晰度。分析了过压历史，火焰强度历史，火焰前沿传播速度，最大火焰强度和峰值爆炸超压。管道中的爆炸可分为两个阶段：初次爆炸和二次爆炸。二次爆炸是由反冲的火焰引起的。周长与反冲火焰的强度和孔板抑制爆炸传播的能力成正比。另外，周长的增加将引起火焰通过孔板的加速，而在孔的周长达到一定值之后，周长的增加对爆炸激发的影响变得不明显。孔板下游的超压（静压）是爆炸强度和湍流共同作用的结果。周长的增加导致孔板下游湍流的增加，这又导致更多的爆炸压力转化为动压。另外，周长的增加将引起火焰通过孔板的加速，而在孔的周长达到一定值之后，周长的增加对爆炸激发的影响变得不明显。孔板下游的超压（静压）是爆炸强度和湍流共同作用的结果。周长的增加导致孔板下游湍流的增加，这又导致更多的爆炸压力转化为动压。另外，周长的增加将引起火焰通过孔板的加速，而在孔的周长达到一定值之后，周长的增加对爆炸激发的影响变得不明显。孔板下游的超压（静压）是爆炸强度和湍流共同作用的结果。周长的增加导致孔板下游湍流的增加，这又导致更多的爆炸压力转化为动压。孔板下游的超压（静压）是爆炸强度和湍流共同作用的结果。周长的增加导致孔板下游湍流的增加，这又导致更多的爆炸压力转化为动压。孔板下游的超压（静压）是爆炸强度和湍流共同作用的结果。周长的增加导致孔板下游湍流的增加，这又导致更多的爆炸压力转化为动压。