金属射流发散性理论分析及数值模拟

The theoretical analysis and numerical simulation of the metal jet incoherence

分析经典射流理论和相关文献,给出了在汇聚点坐标系中金属Cu对碰形成射流的汇聚射流区、无射流激波封锁区、无射流强度封锁区和形成发散射流区域。对金属超声速射流形成的发散性问题进行了理论分析,诠释了Walker基于实验提出射流发散理论,证明了金属射流超声速部分可形成发散射流也可形成汇聚射流,且超过1.23倍体声速的金属射流必定是发散的。最后,应用自编的欧拉计算程序MEPH对金属Cu以不同速度、倾角对碰射流形成过程进行数值模拟,得到了分叉射流、空洞射流和密实稀疏射流等的典型射流发散模式图像,印证了理论分析的结果。

By the analysis of the classic jet theory and literature, the regions of no-jet, convergent jet and incoherent jet are given by calculation of copper in convergent point coordinate system. Theoretical anal- ysis on the incoherence problem of metal supersonic jet formation explains Walker＇s experiment pro- posed jet incoherence theory, and proves that the supersonic portion of the metal jet can form an incoher- ence jet,but convergence jet may also be formed. When the collision velocity is more than 1.23 times the speed of the body-sound, the metal jet must be incoherent. At last the numerical simulation of the copper jet formation process at different speeds and angles is done using ourselves Euler calculation program ＂ MEPH＂. The typical images of bifurcated jet,hollow jet and dense rarefaction jet are given by calcula- tions to confirm the theoretical analysis results.