Investigations On Working Characteristics Of Air-breathing Continuous Rotating Detonation Engine

Air-breathing continuous rotating detonation engine is investigated through numerical simulations combined with experimental studies. Analysis on the initiation process, flow field morphology and the detonation propagation characteristics are conducted. Influences of different experimental parameters and geometric configurations on the engine’s performance are also compared and investigated.Continuous rotating detonation engine(CRDE) with the injection panel is simulated and the flow field characteristics during the stable propagation when the fuel is injected from the top consist of detonation wave, oblique shock wave, triangular region of combustible gas and the interface of the gas and the products of last cycle of reaction. The detonation surface can reach the top of the combustion chamber and expand only at the bottom because of the constraint of the top panel. Comparatively, the detonation surface expands both in the two directions along the axis and induces oblique shock waves when the fuel is injected downstream. Injection location controls the detonation region and the axial distribution of detonation but has little effect on flow field structure and propagation process.Three-dimensional simulations are conducted on the initiation process. It is found that the initiation process is simpler when the initial hot jet does not induce the detonation wave in the opposite direction., taking less time from ignition to stable propagation of detonation. The number of detonation heads is not relevant to that of ignition regions and the continuous detonation wave engine(CDRE) is capable of self-adaption. With supersonic incoming flow, the detonation wave can rotationally propagate continuously. The high-pressure combustion products can influence the air-breathing process and induce normal shock wave in the acceleration section. The influences of stagnation temperature of incoming flow, combustion chamber radius and the location of heat release are investigated. It is found that when the stagnation temperature is higher, the location of the normal shock in the acceleration section is nearer the downstream and the average exit pressure is lower. When the combustion chamber’s radius is smaller, the detonation is influenced by curvature more seriously and the difference between the peak pressures of inner and outer surface of the chamber is more significant. When the combustion region is located in the divergent section, the average pressure of combustion chamber is lower and the normal shock in the acceleration section is located more downstream.Stable work of CRDE is realized under the air-breathing model. The frequency of propagation is 5kHz and the average propagation speed is 1600m/s. Keeping the equivalence ratio constant, the propagation speed slightly increases and the propagation stability is enhanced with increasing mass flux of the propellant. The influences of stagnation temperature of incoming flow, combustion chamber radius, the location of ignition, and the area ratio of acceleration section and the nozzle are investigated. It is found that the engine performance is weakened due to the stronger shock wave and thus the larger total pressure loss when the stagnation temperature of incoming flow is higher and the heat release region is located in the divergent section, and also when the area ratio of acceleration section is smaller. The combustion chamber radius influences the mass flux and the thrust through varying the inlet area but has little effect on the specific impulse. The engine performance is augmented when the area ratio of the nozzle is large because of the further acceleration of the combustion products.