Inlet flow characteristics analysis of air-breathing rotating detonation engine

The influence of unsteady pulsating high pressure in the air-breathing rotating detonation engine combustor on the flow characteristics of inlet is analyzed to guide the design of the inlet. The temporal-spatial characteristics of the pressure in the outlet section of inlet were considered, and the propagation processand flow characteristics of the moving shock wave in the inlet were simulated by adopting the three-dimensional unsteady numerical simulation method. The shape characteristics, propagation velocity, pressureand other key parameters of the moving shock wave were analyzed, and the flow lossand the influence of the angular frequency, peakand time-average values of the pulsating back pressure on the flow characteristics were obtained. It was found that the moving shock wave led to the flow characteristics of low-pressure airflow pressurizationand decelerationand high-pressure airflow decompressionand acceleration in the inlet. Compared with the steady back pressure condition, the influence boundary of pulsating back pressure was more upstream. The higher the angular frequency, the longer the circumferential length, the narrower the width of the oscillation region, the more times the flow passed through the shock wave; however, the average total pressure loss of the outlet at different angular frequencies basically remained unchanged. When the angular frequencyand the time average pressure ratio were respectively kept constant at 12 000 rad/sand 19.1and the pressure peak value ranged from 0.5 to 1 Mpa, the average total pressure loss of the outlet varied from 43% to 46%. When the angular frequencyand peak pressure ratio were respectively kept constant at 12 000 rad/sand 49.5and the time-average pressure increased from 0.22 to 0.32 MPa, the average total pressure loss of the outlet decreased from 52% to 40%. Compared with the steady back pressure condition, the total pressure loss was 2% to 8% larger. The results show that the unsteady pulsating back pressure leads to the big differences between the flow characteristics of the air-breathing rotating detonation engine inletand the traditional engine inlet. In the inlet of air-breathing rotating detonation engine, the flow loss is larger, and the influence boundary of shock wave is closer to the upstream.