脉冲爆震发动机外流场数值模拟及实验

Computational and experimental studies on the external flow filed of pulse detonation engines

关键词:  脉冲爆震发动机  爆炸力学  流场可视化  悬吊激波  数值仿真

Key words:  Pulse detonation engine  Mechanics of explosion  Flow field visualization  Suspended shock  Numerical simulation

摘要:

通过实验和数值方法,对脉冲爆震发动机(Pulse Detonation Engine,PDE)外流场进行了可视化研究。实验中采用YA-16高速阴影系统,拍摄了爆震外流场的时序阴影照片。对高温火团引发的氢气-氧气-氮气爆震过程和管内、外流场分布进行轴对称数值模拟,其中考虑了包含19个基元反应和9种组份的H2-O2-N2详细化学反应动力学机理。根据计算结果,由计算光学获得爆震外流场的时序计算阴影图。数值计算结果和实验结果基本一致,均形象地描述了管外流场的变化。根据实验和数值计算结果,详细地讨论了涡环和悬吊激波产生的动力学机理及其发展变化过程。

Abstract:

The external flow field was visualized using the experimental and numerical method.The YA-16 high speed shadowgraph system was adopted in test to obtain the consequential clear shadowgraphs of the external flow field.Moreover,by solving axisymmetric Navier-Stokes equations in conjunction with the chemistry,a numerical simulation of pulse detonation process induced by flame in the tube with H2-O2-N2 mixture and the distribution of the internal and external flow field was performed,and a detailed chemical mechanism of H2-O2-N2 system,which included 19 element reactions and 9 species,was involved.Based on the numerical results,the computational shadowgraphs were obtained through computational flow images.Comparisons of the computational shadowgraphs with the experimental shadowgraphs show good agreement in trend.Both the experimental and the computational shadowgraphs visually demonstrate the development of the external flow field.Based on the experimental and numerical results,the dynamics mechanism of the occurrence and development of the vortex ring and the suspended shock is elucidated systematically.