Parametric Effects on Internal Aerodynamics of Lobed Mixer-Ejector With Curved Mixing Duct

Abstract

The internal flow characteristics inside lobed mixer-ejector with curved mixing duct and the parametric effects on the lobed mixer-ejector performance are investigated numerically and validated by experimental test. The cwved mixing duct ajfects the development of the streamwise vortices induced by the lobed mixer. When the mixing process undergoes the transition from the straight section to the bent section, the flow inside the cwved mixing duct is dominated by the impinging and centrifugal ejfects. In general, the pumping ratio is decreased approximately 20%-30% once the bent section is mounted on the straight duct. The mixer-ejector performance could by improved by increasing the straight section length, due to more fully momentum utilization of primary jet and weaker influence of bent section on the back pressure near nozzle exit. The mixer-ejector pumping capacity is also augmented with the increase of mixing duct area ratio until the area ratio is reached to 3.5. And the fully-utilization of primary jet momentum inside mixing duct with big area ratio needs long mixing distance. The pumping ratio is decreased as the increase of bent angle of curved mixing duct in approximately linear relationship. When the bent angle exceeds 45 deg, the thermal mixing efficiency is decreased rapidly as the increase of bent angle.