Abstract: Abstract A preliminary experimental study on aerodynamic characteristics of internal flow in ejector composed of curved mixing duct and lobed nozzle or round nozzle is presented in this paper.The results show that:(1)in comparison with the lobed nozzle,its ejector pumping efficiency is enhanced up to about 100% and the relative temperature peak value at its mixing duct exit is cut down to about 10% whereas the total pressure loss is almost the same.(2)due to the generation of the secondary flow induced by curved duct and the spreading effect caused by the primary flow impingement to curved walls,the temperature near the trailing edge is obviously higher than that near the front edge at the major axes of elliptical mixing duct exit,while the temperature distribution takes a saddle shape at the minor axes.