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mozafarie March 9, 2013 08:38

Turbulent flow in tube and laminar flow in annulus
Hi.I want to model heat transfer in a double pipe that turbulent flow of water is in the inner tube and laminar flow is in the can i do this with fluent?

Far March 9, 2013 08:46

If you can keep Yplus below 1, then try transition model.

Fluent has option to model both option in same model. You just need to define two fluids I guess.

mozafarie March 9, 2013 09:01

thanks for your help but my problem is in selecting viscous model turbulent and laminar flow simultaneously in tube an annulus respectively.

taxalian March 9, 2013 14:53

Can you elaborate your problem a little bit more, because i think you need to specify either two different inlet boundary conditions or the alternate option i can tell you seeing your geometry or computational domain.

mozafarie March 10, 2013 06:41

1 Attachment(s)
here's the more details about problem.There is a double pipe that hot water by turbulent flow goes through the inner tube and cold water by the laminar flow goes through annulus (between outer tube and inner tube) and heat transfers between two fluids now i want to model this by fluent and wanted to know how to choice viscous model for each region of fluid.

taxalian March 10, 2013 07:16

Hi mozafarie,
thanks for giving more information.
The working fluid is water. You need to specify the materials for the inner and the outer pipe. These materials are assumed to have the same density and heat capacity , but obviously different thermal conductivities.

You need to change the thermal conductivities of the two pipe surfaces that you model as solid. In addition you use two different fluid b.c's i.e one for the cold fluid letu say 20C
Also turn on the energy equation option and choose the Reliazable k-epsilon turbulence model. You donot have to worry about how you specify the turbulent and laminar region this will be taken care by the boundary condition you specify and the eddy viscosity turbulence model will detect the laminar and turbulent flow internally.

Do remember that you should use pressure based solver and specify the fluid material properties i.e water in your case properly like density, cp, thermal conductivity and viscosity.

Define your first fluid inlet b.c for cold flow . That means velocity inlet and specify the velocity in the momentum tab followed by the choosing turbulent specification method as turbulent intensity and hydraulic diameter. Secondly choose the thermal tab and specify the temperature. Similar approach for the hot flow should be followed.

For the walls of the pipe under the thermal tab you need to choose 0 W/m2.

I hope this helps and wish you good luck.

mozafarie March 10, 2013 07:31

Hi taxalian.
I appreciate it.My problem was solved for your good help.
thanks a lot

taxalian March 10, 2013 07:56

ok thats good to know at least its helpful to you.

best of luck

m7566 November 25, 2014 02:58


Originally Posted by mozafarie (Post 412904)
Hi taxalian.
I appreciate it.My problem was solved for your good help.
thanks a lot

sir will u give me jou file of gambit and case and data file of fluent i have also similar type proble sir my mail i
sir please help me

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