Flow in pipe elbow

Martin1 · May 2, 2015, 06:58

Hi,

I have run steady RANS, simulating the flow in fluent in a bent pipe but the velocity does not seem to be right. There should be a secondary motion of the flow due to centrifugal effects and pressure gradient near the wall. So the inlet, which is the top side of the nozzle, should not look like this.

I have attached a picture here of the velocity profile. Maybe someone can tell me what is going on.

I have used both realizable k-epsilon and SST k-omega, and the result is pretty much the same. The inlet boundary conditions was set as mass flow 0.002 kg/m3 for a quarter model which then was interpolated into this model shown in the picture. This is single flow with diesel as material.

velocity.jpg

edoan · May 6, 2015, 16:14

looks ok to me. to see secondary flow better use x y or z velocity ( i cant quite tell where the axis is pointing) instead of magnitude.

Mustafa1986 · May 6, 2015, 16:20

If the velocity is interpolated then, the inlet should look differently, higher velocity in the core

May 2, 2015, 06:58	Flow in pipe elbow	#1
Martin1 Member Martin Join Date: May 2015 Posts: 30 Rep Power: 11	Hi, I have run steady RANS, simulating the flow in fluent in a bent pipe but the velocity does not seem to be right. There should be a secondary motion of the flow due to centrifugal effects and pressure gradient near the wall. So the inlet, which is the top side of the nozzle, should not look like this. I have attached a picture here of the velocity profile. Maybe someone can tell me what is going on. I have used both realizable k-epsilon and SST k-omega, and the result is pretty much the same. The inlet boundary conditions was set as mass flow 0.002 kg/m3 for a quarter model which then was interpolated into this model shown in the picture. This is single flow with diesel as material. velocity.jpg

May 6, 2015, 16:20		#3
Mustafa1986 New Member Mustafa Join Date: Apr 2015 Posts: 4 Rep Power: 11	If the velocity is interpolated then, the inlet should look differently, higher velocity in the core Last edited by Mustafa1986; May 6, 2015 at 16:29. Reason: …

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May 6, 2015, 16:14		#2
edoan Member Ethan Doan Join Date: Oct 2012 Location: Canada Posts: 90 Rep Power: 14	looks ok to me. to see secondary flow better use x y or z velocity ( i cant quite tell where the axis is pointing) instead of magnitude.