煤油液滴直径对两相旋转爆轰发动机流场的影响

To investigate the influence of the initial droplet diameter on the flow field of gas-liquid two-phase rotating detonation engine, an Eulerian-Lagrangian model of unsteady two-phase detonation is established based on the assumption of an initially uniform droplet diameter and considering atomization and evaporation processes. Non-premixed two-dimensional numerical simulations of detonation for liquid kerosene and high temperature air mixture are conducted. The results show that a single stable rotating detonation wave is formed in the initial droplet diameter range of 1–70 µm. For the global equivalent ratio of 1, the air area before the detonation wave front is larger than the vapor area of kerosene droplets, resulting in inhomogeneous mixing before the wave front. Both oil-rich and oil-poor areas form before the wave front. Due to the speed difference between two phases of the gas and droplets, the air is separated to form a low-temperature strip. When the initial diameter of kerosene droplets is small, the mixing process of reactants is mainly affected by evaporation and the detonation wave propagates stably. When the initial droplet diameter is reduced to 1 µm, evaporation occurs at the entrance, and the rotating detonation flow field shows the characteristics of gas phase propagation, and the structure of the detonation wave is smooth. When the initial diameter of kerosene droplets is relatively large, the mixing process of reactants before the wave front is mainly affected by droplet break-up. For the same fuel mass flow rate with different initial droplet diameters, the maximum residence time of kerosene droplets accounts for more than 80% of the detonation wave propagation time and the detonation velocity increases with the increased ratio of gaseous part of the fuel. The velocity of the detonation wave increases first and then decreases with the increased initial droplet diameter in the range of 10–70 µm.