Density base/pressure base

zxcvasdf · April 27, 2016, 17:37

Hi i want to model a pipe that air flows in and other pipe inside this pipe that contain water flow.The mach number of air is 4,and
my problem is that i want to simulate in fluent and what should i choose density based or pressure based method to solve this problem?
what are the other ways to simulate this physic?
Thanks

mprinkey · April 27, 2016, 19:41

If this is a two-phase flow, I think you are going to have to use the pressure-based solver. If memory serves, none of the Fluent does not support any multiphase capabilities in the density-based solver.

But honestly, you are looking at Mach 4 air flow in a pipe mixed with liquid water?

zxcvasdf · April 28, 2016, 05:37

No water flows in pipe 1 and air is in pipe 2 ,but the pipe 2 is inside pipe 1(concentric) .It means segregate flows.
we have need to calculate heat transfer.

mprinkey · April 28, 2016, 09:16

OK, that makes more sense. Generally, the density based solver works better for highly compressible flows. I think there is enough preconditioning done in the density-based solver to let it work reasonably well at slow speeds for the water side. I'd probably start there.

Good luck.

arjun · April 28, 2016, 21:26

Quote:

Originally Posted by zxcvasdf

No water flows in pipe 1 and air is in pipe 2 ,but the pipe 2 is inside pipe 1(concentric) .It means segregate flows.
we have need to calculate heat transfer.

Edited to remove the answer as it will not work.

You would have to create very thin solid layer in between.

arjun · April 28, 2016, 21:35

BTW in my solver I think you can do it. I will try when I get time.

April 27, 2016, 17:37	Density base/pressure base	#1
zxcvasdf Member zxc Join Date: Mar 2015 Posts: 35 Rep Power: 11	Hi i want to model a pipe that air flows in and other pipe inside this pipe that contain water flow.The mach number of air is 4,and my problem is that i want to simulate in fluent and what should i choose density based or pressure based method to solve this problem? what are the other ways to simulate this physic? Thanks

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April 27, 2016, 19:41		#2
mprinkey Senior Member Michael Prinkey Join Date: Mar 2009 Location: Pittsburgh PA Posts: 363 Rep Power: 25	If this is a two-phase flow, I think you are going to have to use the pressure-based solver. If memory serves, none of the Fluent does not support any multiphase capabilities in the density-based solver. But honestly, you are looking at Mach 4 air flow in a pipe mixed with liquid water?

April 28, 2016, 05:37		#3
zxcvasdf Member zxc Join Date: Mar 2015 Posts: 35 Rep Power: 11	No water flows in pipe 1 and air is in pipe 2 ,but the pipe 2 is inside pipe 1(concentric) .It means segregate flows. we have need to calculate heat transfer.

April 28, 2016, 09:16		#4
mprinkey Senior Member Michael Prinkey Join Date: Mar 2009 Location: Pittsburgh PA Posts: 363 Rep Power: 25	OK, that makes more sense. Generally, the density based solver works better for highly compressible flows. I think there is enough preconditioning done in the density-based solver to let it work reasonably well at slow speeds for the water side. I'd probably start there. Good luck.

April 28, 2016, 21:35		#6
arjun Senior Member Arjun Join Date: Mar 2009 Location: Nurenberg, Germany Posts: 1,272 Rep Power: 34	BTW in my solver I think you can do it. I will try when I get time.