Stable detonation wave propagation in rectangular-cross-section curved channels
Stable detonation wave propagation in rectangular-cross-section curved channels
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DOI：
10.1016/j.combustflame.2011.07.022
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发表时间：
2012-02
影响因子：
4.4
通讯作者：
H. Nakayama;Takahiro Moriya;J. Kasahara;A. Matsuo;Y. Sasamoto;I. Funaki
中科院分区：
文献类型：
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作者：
H. Nakayama;Takahiro Moriya;J. Kasahara;A. Matsuo;Y. Sasamoto;I. Funaki
为了确定稳定的传播条件，对弯曲通道内的爆轰传播现象进行了实验研究。采用化学计量乙烯-氧混合气体和5种不同曲率半径的矩形截面弯曲通道。利用高速摄像机对爆震波在弯曲通道中的传播过程进行了可视化研究。为了同时观测爆震波的前激波形状和爆震波上三个点的运动轨迹，本研究发展了多帧短时间开快门摄影技术（MSOP）。当混合气体的填充压力增大或弯曲通道的内曲率半径增大时，爆震波更加稳定。爆震波传播模式由不稳定向稳定过渡的临界条件是弯曲通道的内曲率半径（ri）等于正常爆轰槽宽度（λ）的21-32倍。在稳定传播模式下，法向爆轰速度（Dn）随距离弯曲通道内壁的距离增加而增加，接近平面爆轰通过弯曲通道直线段传播的速度（Dstr）。在内壁上观察到最小的dna，并且随着ri/λ的减小而减小。对稳定模态下爆震波的分布进行了近似计算。公式给出的近似解与实验结果吻合较好。利用该公式可以准确地重建爆震波的前激波形状。λ非量维化的爆震波局部曲率（κ）随爆震波与内壁距离的增加而减小。λκ在细胞内壁最大，且随ri/λ的增加而增加。Dn/ dstrn随λκ的升高而降低。这种无量纲化的Dn -κ关系几乎与ri/λ无关。
The detonation propagation phenomena in curved channels were experimentally studied in order to determine the stable propagation condition. A stoichiometric ethylene–oxygen mixture gas and five types of rectangular-cross-section curved channels with different inner radii of curvature were employed. The detonation waves propagating through the curved channels were visualized using a high-speed video camera. Multi-frame short-time open-shutter photography (MSOP) was developed in the present study to simultaneously observe the front shock shape of the detonation wave and the trajectories of triple points on the detonation wave. The detonation wave became more stable under the conditions of a higher filling pressure of the mixture gas and/or a larger inner radius of curvature of the curved channel. The critical condition under which the propagation mode of the detonation wave transitioned from unstable to stable was having an inner radius of curvature of the curved channel (ri) equivalent to 21–32 times the normal detonation cell width (λ). In the stable propagation mode, the normal detonation velocity (Dn) increased with the distance from the inner wall of the curved channel and approached the velocity of the planar detonation propagating through the straight section of the curved channel (Dstr). The smallest Dnwas observed on the inner wall and decreased with decreasing ri/λ. The distribution of Dnon the detonation wave in the stable mode was approximately formulated. The approximated Dngiven by the formula agreed well with the experimental results. The front shock shape of the detonation wave could be reconstructed accurately using the formula. The local curvature of the detonation wave (κ) nondimensionalized by λ decreased with increasing distance from the inner wall. The largest λκ was observed on the inner wall and increased with increasing ri/λ. Dn/Dstrdecreased with increasing λκ. This nondimensionalized Dn–κ relation was nearly independent of ri/λ.