To understanding the initiating process in the pulse detonation curved-chamber and rotating detonation chamber, this article conducted an experimental study on the flame acceleration and the transition to detonation in the annular channel. With different equivalence ratios of acetylene-air and acetylene-oxygen as explosive mixtures, based on high-speed photography and shadow technology, the propagation characteristics of combustion waves in the annular channel were analyzed by the use of high-speed photography and shadow image technology. The results showed that only low-speed flame was formed in the 360° annular channel filled with the acetylene-air mixture. The flame propagation characteristics were affected by the reflection of compression waves in the pipeline. When the annular channel exit was closed, the interaction between the stronger compression waves and the flame front destroyed the flame structure and formed a “flame kernel” at the boundary layer. When the annular channel exit was open, the interaction between the weak compression waves and the flame front only made the flame front more wrinkled. A deflagration to detonation transition process was observed in the annular channel for the acetylene-oxygen mixture. In contrast, detonation can only be triggered in the longer straight tube under the same condition. The self-ignition of the unreacted band-shaped zone between the outer wall of the channel and the flame front was the key to initiate the detonation in the annular channel.

为了解脉冲爆轰弯曲室和旋转爆轰室的起爆过程，本文对环形通道中的火焰加速和向爆轰转变进行了实验研究。以不同当量比的乙炔-空气和乙炔-氧气为爆炸性混合物，基于高速摄影和阴影技术，利用高速摄影和阴影图像技术分析了燃烧波在环形通道中的传播特性. 结果表明，在充满乙炔-空气混合物的360°环形通道中仅形成低速火焰。火焰传播特性受管道内压缩波反射的影响。当环形通道出口关闭时，较强的压缩波与火焰锋面的相互作用破坏了火焰结构，在边界层形成了“火焰核”。当环形通道出口打开时，弱压缩波与火焰前缘之间的相互作用只会使火焰前缘更加起皱。在乙炔-氧气混合物的环形通道中观察到从爆燃到爆轰的转变过程。相比之下，在相同条件下，只能在较长的直管中触发爆轰。通道外壁与火焰前缘之间未反应带状区的自燃是引发环形通道起爆的关键。弱压缩波与火焰锋面的相互作用只会使火焰锋面更加褶皱。在乙炔-氧气混合物的环形通道中观察到从爆燃到爆轰的转变过程。相比之下，在相同条件下，只能在较长的直管中触发爆轰。通道外壁与火焰锋之间的未反应带状区的自燃是引发环形通道起爆的关键。弱压缩波与火焰锋面的相互作用只会使火焰锋面更加皱折。在乙炔-氧气混合物的环形通道中观察到从爆燃到爆轰的转变过程。相比之下，在相同条件下，只能在较长的直管中触发爆轰。通道外壁与火焰前缘之间未反应带状区的自燃是引发环形通道起爆的关键。