Initiation and sustaining mechanisms of stabilized Oblique Detonation Waves around projectiles
Initiation and sustaining mechanisms of stabilized Oblique Detonation Waves around projectiles
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DOI：
10.1016/j.proci.2012.05.035
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
S. Maeda;S. Sumiya;J. Kasahara;A. Matsuo
中科院分区：
文献类型：
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作者：
S. Maeda;S. Sumiya;J. Kasahara;A. Matsuo
用1.06- 1.31倍C-J速度的球形粒子直接激发和稳定三维锥形爆轰波。我们进行了高时间分辨率的纹影可视化的整个过程中的非定常启动稳定的斜爆轰波（ODWs）的稳定传播使用高速摄像机。可引爆的混合物是化学计量的氧与乙炔、乙烯或氢的混合物。将它们用氩气稀释至50%体积分数，并且还测试了75%稀释的混合物的乙炔/氧气。在稳定ODW的起爆过程中，出现了弹丸直接起爆爆轰和类似二次起爆的DDT过程。这一过程最终导致由弹丸速度支持的稳定的ODW和起源于二次起爆的环形爆轰波。基于C-J速度和角度，模拟了稳定ODW在二次起爆后的空间演化。该模型定性地再现了稳定的ODW的测得的发展速率。本文还讨论了稳定爆轰波在弹体周围的三维特性所引起的曲率效应对爆轰稳定性的影响。曲率效应使爆轰波在弹丸附近衰减到C-J速度以下。曲率效应的传播极限将决定获得稳定ODW的临界性。通过获得传播速度和曲率半径的详细分布，实验表明，对于50%氩或75%氩/氪稀释的混合物，由单元尺寸归一化的临界曲率半径为8-10或15-18。
Direct initiations and stabilizations of three-dimensional conical detonation waves were attained by launching spheres with 1.06–1.31times the C–J velocities into detonable mixtures. We conducted high time-resolution Schlieren visualizations of the whole processes over unsteady initiations to stable propagations of the stabilized Oblique Detonation Waves (ODWs) using a high-speed camera. The detonable mixtures were stoichiometric oxygen mixtures with acetylene, ethylene or hydrogen. They were diluted with argon in a 50% volumetric fraction, and a 75% diluted mixture was also tested for the acetylene/oxygen. The direct initiation of detonation by the projectile and the DDT process like the re-initiation appeared in the initiation process of stabilized ODW. This process eventually led to the stabilized ODW supported by the projectile velocity and the ringed shape detonation wave originating in the re-initiation. We modeled the spatial evolution of stabilized ODW after the re-initiation based on its C–J velocity and angle. The model qualitatively reproduced the measured development rate of stabilized ODW. We also discussed about the detonation stability for the curvature effect arising from the three-dimensional nature of stabilized ODW around the projectile. The curvature effect attenuated the detonation wave below its C–J velocity at the vicinity of projectile. The propagation limits of curvature effect will be responsible for the criticality to attain the stabilized ODWs. By accessing the detailed distributions of propagation velocities and curvature radiuses, the critical curvature radiuses normalized by the cell sizes experimentally revealed to be 8–10 or 15–18 for mixtures diluted with each 50% argon or 75% argon/krypton.