# Turbulent flow in tube and laminar flow in annulus

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 March 9, 2013, 08:38 Turbulent flow in tube and laminar flow in annulus #1 New Member   shahab Join Date: Mar 2012 Posts: 13 Rep Power: 7 Sponsored Links 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 annulus.how can i do this with fluent?

 March 9, 2013, 08:46 #2 Super Moderator   Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,329 Blog Entries: 6 Rep Power: 45 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. Last edited by Far; March 9, 2013 at 09:14.

 March 9, 2013, 09:01 #3 New Member   shahab Join Date: Mar 2012 Posts: 13 Rep Power: 7 thanks for your help but my problem is in selecting viscous model turbulent and laminar flow simultaneously in tube an annulus respectively.

 March 9, 2013, 14:53 #4 Senior Member   Join Date: Nov 2010 Posts: 135 Rep Power: 8 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.

March 10, 2013, 06:41
#5
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shahab
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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.
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 double pipe.bmp (57.4 KB, 29 views)

 March 10, 2013, 07:16 #6 Senior Member   Join Date: Nov 2010 Posts: 135 Rep Power: 8 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 20°C 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.

 March 10, 2013, 07:31 #7 New Member   shahab Join Date: Mar 2012 Posts: 13 Rep Power: 7 Hi taxalian. I appreciate it.My problem was solved for your good help. thanks a lot

 March 10, 2013, 07:56 #8 Senior Member   Join Date: Nov 2010 Posts: 135 Rep Power: 8 ok thats good to know at least its helpful to you. best of luck salehorafi likes this.

November 25, 2014, 02:58
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manish sharma
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Quote:
 Originally Posted by mozafarie 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 m9713001413@gmail.com

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