EXPERIMENTAL INVESTIGATION ON GASEOUS DETONATION PROPAGATION THROUGH A T-SHAPE BIFURCATED TUBE
气相爆轰在T形管中传播新现象的实验研究

The gaseous detonation of 2H$_{2}$/O$_{2}$/Ar mixture propagation through a T-shape bifurcated tube with a square cross-section 40\,mm$\times $40\,mm has been experimentally studied in this paper. The pressure histories at the specific ports were recorded by pizeo-electric transducers and cellular patterns around the T-shape were recorded by smoked foils respectively. The average velocity of detonation and the cell evolution were obtained. Experimental results indicate that the detonation wave is strongly weakened by the geometry around the T-shape tube. The interactions of leading shock and transverse waves contribute to the traveling characteristics of detonation. In the downstream region far away from 3.5 to 6 times the tube cross-section size, a secondary steady detonation wave is re-established accompanying the appearance of regular cellular structures with the same sizes as the previous one. The cellular patterns also demonstrate the phenomena of diffraction, regular and Mach reflections of gaseous detonation. In the pass-by tube, it is noted that the cellular structure disappears in the region just downstream the start of the T-shape due to the separation of leading shock and reaction zone. With the propagation and reflection of the leading shock in the pass-by tube, the re-initiation occurs in the separated region between the leading shock and reaction zone. The re-initiation can be demonstrated by the clustered cellular structures on the smoked-foils, and it is critical in re-establishing of gaseous detonation here. As the initial pressure decreases to 2.00\,kPa, the steady detonation can be re-established in downstream region, but detonation extinguishes in the bifurcated tube. Also, based on the smoked foil records, several characteristic lengths and angles were measured and the initial pressure influences on them were analyzed.