Investigation on Ejecting and Mixing Characteristics of Lobed Nozzle with Curved Mixing Duct and Slot Exit

A combined experimental and computational study on ejecting and mixing characteristics of the lobed nozzle with curved mixing duct and slot exit was performed.The velocity fields,pressure fields and temperature fields,as well as the ejection coefficient and pressure recovery coefficient which reflect the overall characteristics of mixer-ejector system were obtained.It is indicated that the relative error between the computational and experimental results is about 15%.As the exit of the curved mixing duct is a narrow slot,the flow process inside mixing duct is affected by streamwise vortices and secondary circulation,which forms some special flow phenomena and features compared to common curved mixing duct with elliptical exit.Because of the existence of secondary flow caused by the curved duct,the streamwise vortices formed at the lobed nozzle trailing edge are strongly destroyed in the developing process,and the velocity and temperature distribution features are not similar to that in short curved mixing duct with elliptical exit.