管道内瓦斯爆炸冲击作用特性数值模拟研究

Numerical simulation research on characteristics of gas explosion shock in tubes

为了掌握管道内瓦斯爆炸冲击作用特性,利用ANSYS/LS-DYNA对浓度为9.5%,填充长度为5 m的瓦斯在管道内爆炸产生冲击作用进行了数值模拟,分析了耦合效应对管道内瓦斯爆炸流场和冲击波超压的影响.研究结果表明:瓦斯爆炸瞬间,管道内坐标分别为A(0,0,2),B(0,0,4)测点的压力瞬间达到峰值,之后测点A,B的压力逐渐减小直至趋近于某一稳定值.而初始压力为大气压的测点C(0,0,6),D(0,0,8),E(0,0,10)依次达到超压峰值后逐渐地衰减趋近于大气压力.因此,在耦合和解耦合的2种情况下,不同测点的超压时程曲线走势基本一致.在解耦合条件下,管道轴向同心环等压线以均匀圆环的形式向开口方向传播;在耦合条件下,管道轴向同心环等压线以紊乱的等压线分布形式向开口端传播.因此,瓦斯爆炸流固耦合效应对冲击波等压线的分布有一定的影响,即改变流场分布.

In order to master the characteristics of gas explosion shock in tubes,induced by the gas whose concentration is 9. 5% and the filling length of which in tubes is 5 m,this process is simulated through the software ANSYS / LS-DYNA. Furthermore,the influence of coupling effects on the flow field of gas explosion and the shock overpressure inside the tube are analyzed. Results indicate that at the moment of gas explosion,the pressure of measuring point A（ 0,0,2）,and B（ 0,0,4）,arranged in the gas regional of tube reaches to peak suddenly,then they decreases to a steady value gradually,while the pressure of measuring point C（ 0,0,6）,D（ 0,0,8） and E（ 0,0,10） decreases to the atmospheric pressure before they reaches to overpressure peak value successively. Therefore,the tendency of the overpressure-time curve keeps consistent between those different measuring points under the coupling and uncoupling condition. The isobar of concentric ring along the axial direction transmits towards the opening direction under the download coupling condition in the form of uniformly circle,but in the form of inordinate isobar under the coupling condition. So,the fluid-solid coupling effect of gas explosion has some influences on the isobar of shock wave,namely the distribution characteristic of isobar is changed.