密闭管道内不同开孔形状的柔性障碍物对可燃气体爆炸特性的影响研究

Study on the Influence of Flexible Obstacles with Different Opening Shapes on the Explosion Characteristics of Combustible Gases in A Confined Duct

为了减少化工工业生产过程中瓦斯爆炸事故导致的巨大损失,研究了在模拟密闭管道(横截面80 mm×80 mm,长度3 m)内不同开孔形状的柔性障碍物对可燃气体爆炸特性的影响机制。选用厚度为0.105 mm,开孔形状分别为圆形、方形、三角形、四齿、六齿、八齿的植物纤维膜为柔性障碍物,阻塞率为75%,以孔隙周长和形状对称特性作为判断孔隙锐度的标准。柔性障碍物的不同开孔形状对爆炸传播有显著影响。分析了甲烷爆炸过程中的超压特性和火焰特点并得出结论。结果说明爆炸波在彻底冲开膜片前产生了多次激波反射和孔隙大小对射流的约束共同作用下,诱导了湍流火焰的产生。另外,通过与空载管道的超压和火焰强度变化趋势对比,发现孔隙柔性障碍物形状决定火焰通过柔性孔隙障碍物的加速度,而在周长和形状为特定一条件下,对爆炸激励的影响不明显。需要注意的是,柔性孔隙障碍物下游的超压是爆炸强度和湍流共同作用的结果。综上所述,柔性障碍物开孔形状对甲烷爆炸的影响表现为一个激励-抑制的特殊机制。柔性障碍物孔隙形状在一定范围内增加显著激励了火焰传播速度,进而导致湍流强度和爆炸强度增加。

In order to reduce the huge loss caused by gas explosion accidents in the process of chemical industry production,the influence mechanism of flexible obstacles with different opening shapes on the explosion characteristics of combustible gas in a simulated closed pipeline(cross section 80 mm×80 mm,length 3 m)was studied.In this paper,the plant fiber membrane with the thickness of 0.105 mm and the opening shape of circle,square,triangle,four-tooth,six-tooth and eight-tooth is selected as the flexible barrier,BR=75%,and pore circumference and shape characteristics are taken as the criteria for judging pore sharpness.Different opening shapes of flexible obstacles have significant effects on explosion propagation.The characteristics of overpressure and flame in the process of methane explosion are analyzed and a conclusion is drawn.The results show that the turbulent flame is induced by the shock wave reflection and the restriction of the pore size before the explosion wave breaks through the diaphragm.In addition,by comparing with the overpressure and flame intensity variation trend of the empty pipe,it is found that the shape of the porous flexible obstacle determines the acceleration of the flame passing through the flexible porous obstacle,but has no obvious influence on the explosion excitation under the condition of specific perimeter and shape.It should be noted that the overpressure downstream of a flexible porous barrier is a result of the combined effect of blast strength and turbulence.In conclusion,the effect of the opening shape of flexible obstacles on methane explosion is a special mechanism of excitation-suppression.The increase of the pore shape of the flexible barrier in a certain range significantly stimulates the flame propagation velocity,which leads to the increase of the turbulence intensity and explosion intensity.