截顶M型药型罩几何参数对射流形成的影响

Influence of geometric parameters of truncated M-shaped liner on jet formation

用有限元显式动力分析程序Autodyn,对截顶M型药型罩在压垮过程中出现的射流多次碰撞现象进行研究,通过改变顶部结构几何参数,对比分析参数对射流汇聚产生的影响,探讨射流碰撞使射流加速的原因。将M型顶部结构截去一部分构成截顶M型药型罩,压垮过程可分为顶部、轴线射流汇聚两部分。结果表明:在足够的碰撞压力下,瞬时二级药型罩结构被压垮,产生速度更高的二次射流,且药型罩顶部高度增大显著提升经多次汇聚后的射流头部速度。顶部结构参数:顶部倒锥角θ、截顶高度h、截顶宽度d的最佳取值分别为60°~90°、8~13 mm、约10 mm。

Numerical simulations were conducted to analyze the phenomenon that jets may collide many times during the crushingp rocess of truncated M-shaped liner with Autodyn. The multiple convergence of jets were compared by changing the geometric parameters of the top structure,in this way,and the reason why the jet collision can accelerate secondary jet was discussed. The top part of a M-shaped liner was cut off to form a truncated M-shaped liner. Its crush can be divided into two stages basically,i.e.,the top jet convergence and the axial jet convergence. The results show that under sufficient collision pressure,the instantaneous secondary liner structure is crushed to generatea higher speed secondary jet,and the increase the height of the top structure observably increase the head velocity of the jet after multiple convergences. The best value ranges of the top structural parameters θ,h and d are 60°-90°,8-13 mm and about 10 mm,respectively.