悬摆法测量微尺度光滑管内爆震冲量的实验研究

Experimental Research on Detonation Impulse Measurements in Micro-Scale Smooth Tubes Using a Ballistic Pendulum

关键词:  脉冲爆震，悬摆法，冲量测量，DDT

Key words:  Micro-scale detonation  Ballistic pendulum  Impulse measurements  DDT

摘要:

为探索微尺度爆震用于空间推进和能量利用的可行性，首次用悬摆法测量了长1m，内径4～10mm的微尺度爆震管内不同当量比下的乙烯-氧气混合物的爆震冲量和比冲，同时与Wintenberger基于直接起爆的爆震冲量计算模型进行了对比验证。结果表明，火焰由缓燃向爆震转变的距离(DDT距离)对冲量有主要的影响。DDT距离越短，冲量越大。在本实验工况下，不同管径下能产生最大冲量的当量比是1.4；如果不考虑DDT的影响，模型计算的冲量与实验值吻合较好。另一方面，冲量与管径成正比，但是管径越小，各个当量比下的冲量差距越小。

Abstract:

In order to research on the possibility of using micro-scale detonation for space propulsion and energy utilization，the detonation impulse/specific impulse of ethylene-oxygen mixtures in micro-scale tubes with a length of 1 m and various inner diameters (4～10 mm) under different equivalence ratios were measured for the first time using a ballistic pendulum. The measured impulses were compared and validated with Wintenberger’s analytical model which is based on direct detonation initiation. The results show that，the deflagration to detonation transition (DDT) distance had a major effect on impulse. As the DDT distance shortened，the impulse became greater. The maximum impulse occurred at the equivalence ratio of 1.4 for all different tubes under the current experimental condition. The impulses calculated by the analytical model were in good agreement with the experimental values as long as the DDT effect was ignored. On the other hand，the detonation impulse was proportional to the tube inner diameter. However，smaller inner diameter could reduce the deviation of the impulses among different equivalence ratios.