To control flow separation inside the lobed mixer with a big lobed angle

ventilating treatment was performed on a baseline lobed mixer to reveal the effectiveness of ventilation on eliminating separation bubble inside the lobed mixer when secondary flow is forced or ejected by numerical simulation. Results show that:(1)When the lobed angle is below 35 degrees

no separation is observed; when the lobed angle is at 35 degrees

separation bubble begin to appear inside the lobed nozzle

when the lobed angle is above 35 degrees

separation bubble augments.(2)Ventilating treatment on lobed forced mixer with a big lobed angle is able to eliminate the separation bubble inside the nozzle.(3)The same treatment on the other hand does not banish the separation bubble inside the lobed ejector mixer with a big lobed angle. In fact

the ventilating gap brings forward the separation phenomena rather than avoiding it.