Aerodynamic Characteristics of the Combined Cycle Engine in an Ejector Jet Mode

Aerodynamic performances of the combined cycle engine model was tested in a subsonic to transonic flow region. In this low speed, the engine works in an ejector jet mode. To simulate ejector eect, gas nitrogen was exhausted from the nozzle which located downstream of the inlet. Wall pressure distributions and Pitot pressure at the exit of the model were measured to grasp basic features of the engine flow field. The fluctuating Pitot pressure was also measured to estimate the mass flow oscillation. Two dimensional CFD was carried out to compare the experimental results and the flow structure inside the inlet was examined. With the current configuration, high pressure region on the ramp which caused the increment of drag, was formed and well predicted by CFD.