Oblique detonation waves stabilized in rectangular-cross-section bent tubes

Oblique detonation waves, which are generated by a fundamental detonation phenomenon occurring in bent tubes, may be applied to fuel combustion in high-efficiency engines such as a pulse detonation engine (PDE) and a rotating detonation engine (RDE). The present study has experimentally demonstrated that steady-state oblique detonation waves propagated stably through rectangular-cross-section bent tubes by visualizing these waves using a high-speed camera and the shadowgraph method. The oblique detonation waves were stabilized under the conditions of high initial pressure and a large curvature radius of the inside wall of the rectangular-cross-section bent tube. The geometrical shapes of the stabilized oblique detonation waves were calculated, and the results of the calculation were in good agreement with those of our experiment. Moreover, it was experimentally shown that the critical condition under which steady-state oblique detonation waves can stably propagate through the rectangular-cross-section bent tubes was the curvature radius of the inside wall of the rectangular-cross-section bent tube equivalent to 14–40 times the cell width.