Flow characteristics of ejector nozzles with different auxiliary intake valves

Abstract

The ejector nozzle requires a third auxiliary airflow to improve its thrust performance at transonic speed. However, different auxiliary air intake structures will affect the third auxiliary flow, which in turn may change its thrust performance and internal flow field characteristics. Herein, we simulated four nozzles with different intake valve structures (sector angles of the open-close interval structure were 30°, 22.5°, 18°, and 15°, respectively) at transonic speed (Ma = 1.2). The results show that there is significant lateral flow inside the nozzle, which induces a multi-pair vortex. In addition, the nozzle with an open-close sector angle of 30° has the largest flow rate of 9.352 kg/s, which produces the largest thrust and the slowest dissipating flow vortex, but the distortion of the flow field in nozzles is the most obvious. However, with the reduction of the sector angle of the open-close intake valves (i.e., 22.5°, 18°, and 15°), the flow rate and the thrust of the nozzle decrease. Meanwhile, the dissipation of the flow vortex is accelerated, resulting in a weakening of the flow field distortion.