In this study, the detonation diffraction and re-initiation processes around a single cuboid were studied experimentally. Experiments were performed in a 6-m-long duct with a cross section of 112 mm × 112 mm filled with stoichiometric methane–oxygen mixtures at initial pressures between 10 and 30 kPa. A cuboid was placed in the duct to form two perpendicular passages between the cuboid and the walls. Soot foils fixed on the side wall and bottom wall were used to characterize the cellular structure evolution process, from which the diffraction and re-initiation behavior of a detonation could be analyzed. The effects of the spacing between the cuboid and the top wall (\(\delta\)) and the spacing between the cuboid and the side wall (\(\sigma\)) on diffraction and re-initiation were investigated systematically. It is shown that the diffraction and re-initiation of a detonation were influenced significantly by introducing a perpendicular channel. Compared with the unidirectional scenario, the boundary between the diffraction wave and the re-initiation region was not so sharp. Depending on the channel scale and mixtures sensitivity (or cell size, \(\lambda\)), two re-initiation modes could be observed. For more sensitive mixtures (\(\delta {/}\lambda > {2}\) or \(\sigma {/}\lambda > 2\)), an overdriven detonation occurs first. The overdriven detonation propagates toward the edge, generating a secondary overdriven detonation near the wall through detonation reflection. The new one propagates forward and decays to a steady-state detonation. On the other hand, only one overdriven detonation occurs for less sensitive mixtures. For a given channel width, it was demonstrated that the diffraction area could be narrowed as the perpendicular channel width was increased. The inverse feedback mechanism between the two perpendicular diffraction waves was analyzed.

在这项研究中，实验研究了围绕单个长方体的爆轰衍射和再引发过程。实验在一个 6 米长的管道中进行，管道的横截面为 112 毫米 × 112 毫米，充满化学计量的甲烷-氧气混合物，初始压力在 10 到 30 kPa 之间。一个长方体被放置在管道中以在长方体和壁之间形成两个垂直的通道。固定在侧壁和底壁上的烟灰箔用于表征蜂窝结构演化过程，从中可以分析爆炸的衍射和再引发行为。长方体与顶壁之间的间距（\(\delta\)）和长方体与侧壁之间的间距（\(\sigma\)) 对衍射和再引发进行了系统的研究。结果表明，引入垂直通道会显着影响爆炸的衍射和重新引发。与单向场景相比，衍射波和重新引发区域之间的边界并不那么尖锐。根据通道规模和混合灵敏度（或细胞大小，\(\lambda\)），可以观察到两种重新启动模式。对于更敏感的混合物（\(\delta {/}\lambda > {2}\)或\(\sigma {/}\lambda > 2\))，首先发生过载爆轰。超驱动爆震向边缘传播，通过爆震反射在壁附近产生二次超驱动爆震。新的向前传播并衰减为稳态爆炸。另一方面，对于不太敏感的混合物，只会发生一次过驱动爆轰。对于给定的通道宽度，已证明随着垂直通道宽度的增加，衍射区域可以变窄。分析了两个垂直衍射波之间的逆反馈机制。