Investigation on the detonation characteristics of reverse-flow pulse detonation combustors via blockage ratio

The reverse-flow pulse detonation combustor (PDC) exhibits a shorter axial length in contrast to the straight-tube PDC, thereby enhancing its suitability for engineering applications. In order to investigate the influence of the blockage ratio of the mixing section on the detonation characteristics of the reverse-flow PDC, a combined approach of numerical calculation and experiment was adopted. The detonation characteristics of the PDC under different blockage ratio schemes were comparatively analyzed. The results show that elevating the blockage ratio can effectively reduce the size of the reverse-flow zone, eliminate the oil entrainment phenomenon. The deflagration to detonation (DDT) distance generally first increases and then decreases as the blockage ratio rises. In contrast to the baseline scenario, for the PDC structure with a blockage ratio of 0.65, the lean flameout limit has a minimum reduction of 35% (at 5 Hz) and a maximum reduction of 59% (at 25 Hz). The rich flameout limit has a minimum reduction of 2% (at 5 Hz) and a maximum reduction of 39% (at 20 Hz). The stable working range is enhanced by a minimum of 1.12 times (at 10 Hz) and a maximum of 2.55 times (at 15 Hz).