Flow rate reduction analysis

hosein-1974 · April 14, 2016, 09:11

Hi all,
I am a new autodesk CFD user. and I want to analyze an air tunnel and my goal is to determine the amount of air out let volume. how i have to defined the boundaries?
mu boundary setup now is:
inlet Volume rate is 900 Cubic meter per hour.
out let pressure 0
all the other wall are set to slip.
But I received almost the same amount in outlet, but in a practical test I have had an almost 50% reduction in air flow.
what would be my mistake or unassign boundary?
Tanks for your help.

W!ldejon · December 21, 2016, 08:02

In reality you have less flow exiting than you do entering?
This could only really be true with a high speed compressible study and only with volumetric flow rate, otherwise you really must have the same volume of flow entering and exiting.

Davidkep · July 29, 2019, 15:16

If the water is coming out out of the tip too fast like a tap, then you can increase the pipe size, it wont slow down the volume at all, but itll make it come out in a better flow rate not messing up the media.

April 14, 2016, 09:11	Flow rate reduction analysis	#1
hosein-1974 New Member hosein Join Date: Apr 2016 Posts: 1 Rep Power: 0	Hi all, I am a new autodesk CFD user. and I want to analyze an air tunnel and my goal is to determine the amount of air out let volume. how i have to defined the boundaries? mu boundary setup now is: inlet Volume rate is 900 Cubic meter per hour. out let pressure 0 all the other wall are set to slip. But I received almost the same amount in outlet, but in a practical test I have had an almost 50% reduction in air flow. what would be my mistake or unassign boundary? Tanks for your help.

July 29, 2019, 15:16	Flow rate reduction analysis	#3
Davidkep New Member Davidkep Join Date: Jul 2019 Location: Burkina Faso Posts: 2 Rep Power: 0	If the water is coming out out of the tip too fast like a tap, then you can increase the pipe size, it wont slow down the volume at all, but itll make it come out in a better flow rate not messing up the media.

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December 21, 2016, 08:02		#2
W!ldejon New Member Jon Wilde Join Date: Dec 2016 Posts: 25 Rep Power: 10	In reality you have less flow exiting than you do entering? This could only really be true with a high speed compressible study and only with volumetric flow rate, otherwise you really must have the same volume of flow entering and exiting.