Based on three dimensional CFD of single/double-stage lobed mixer-ejector with fixed mixing duct area ratio and length ratio

the effects of fundamental structure parameters on pumping performance were investigated. The results showed that the pumping ratio of double-stage lobed mixer-ejector increased when main stream velocity or lobe diffusion angle rose. The first stage pumping capacity for double-stage lobed mixer-ejector was stronger than single-stage lobed mixer-ejector

meanwhile the total pumping ratio of double-stage lobed mixer-ejector was 100% superior to that of single-stage one. Besides

the maximum vorticity and the velocity circulation became larger with the increase of primary flow velocity. In the direction of main stream

the maximum vorticity of single-stage mixer declined gradually

while the velocity circulation firstly increased and then decreased. However

in the double-stage lobed mixer-ejector

both maximum vorticity and velocity circulation decreased along main stream

with a much higher decreasing speed in the first stage nozzle. What's more

the thermal mixing efficiency declined as primary flow was attached to wall much earlier due to the increase of main stream velocity or lobe diffusion angle. For double-stage lobed mixer-ejector

the thermal mixing efficiency at mixing duct exit section was 6% superior in comparison with single-stage one

though the thermal mixing efficiency of double-stage lobed mixer-ejector rose at a low speed along mixing duct.