Effects of different physical properties of anthracite powder fuel on detonation characteristics of a rotating detonation engine

The rotating detonation engine (RDE) fueled by coal powder has attracted much attention because of its high thermal cycle efficiency. To explore the detonation characteristics of anthracite powder and further study the effects of particle size and morphology on them, a series of rotating detonation experiments with anthracite powder were carried out in a disk-shaped combustor. The experimental results show that the morphology of anthracite particles plays an important role in detonation. The addition of porous anthracite (PA) enhances the detonation intensity in the lean hydrogen-air, while flaky anthracite (FA) weakens it. The concentration rise of PA increases the detonation wave height, while FA does not have such an obvious effect on the height. The excessive addition of any anthracite powder increases the heat loss of the detonation, resulting in a decrease in detonation velocity. By comparing the detonation characteristics of 20-nm, 3-mu m, and 40-mu m PA, it is found that the detonation performance of 20-nm PA, which has strong agglomeration, has no significant advantages over the micron-sized PA. Among the three PA powders, 3-lm PA has the largest detonation intensity and velocity. The difference in engine performance caused by pulverized anthracite with different morphological characteristics is as follows: when the mass flow rates of coal, H-2, and air are 6.7, 5.3, and 260 g/s, respectively, the specific impulse of 3-mu m PA reaches 7.8 kN center dot s/kg, which is about 2.7 times higher than that of 5-mu m FA. This research provides theoretical guidance for the powder fuel selection of the RDE.