finned tube simplification

hmasenger · January 26, 2014, 10:37

hi all
i am modeling a shell and tube heat exchanger and i have found that finnes installed on tubes play a great roll in heat exchanging process and neglecting theme would lead to unreal results .the problem is with modeling finnes that leads to extremely small cells and outnumbered elements!
does anyone know is there a way to simplify the pressure drop in Finns and heat transfer coefficient(h)?

any tip or suggestion would be greatly appreciated

ghorrocks · January 27, 2014, 17:10

Source terms, both on momentum and heat equations. You might also be able to use a convection condition on the energy equation where h has been modified to account for the fins.

hmasenger · January 28, 2014, 17:28

would you pleas give me a sample,link,key words or something that could guide? i have no idea how to modify discretized equations and source terms defined in CFX.

ghorrocks · January 28, 2014, 17:32

Read the documentation on source terms. The convection coefficient approach is simply the convection boundary condition.

You might also be able to do this using a thermal resistance on the interface.

All of this is explained in the documentation.

hmasenger · January 28, 2014, 17:42

tnx i will check that out

January 26, 2014, 10:37	finned tube simplification	#1
hmasenger Senior Member hamed Join Date: Apr 2009 Posts: 148 Rep Power: 17	hi all i am modeling a shell and tube heat exchanger and i have found that finnes installed on tubes play a great roll in heat exchanging process and neglecting theme would lead to unreal results .the problem is with modeling finnes that leads to extremely small cells and outnumbered elements! does anyone know is there a way to simplify the pressure drop in Finns and heat transfer coefficient(h)? any tip or suggestion would be greatly appreciated

January 27, 2014, 17:10		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	Source terms, both on momentum and heat equations. You might also be able to use a convection condition on the energy equation where h has been modified to account for the fins. hmasenger likes this.

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January 28, 2014, 17:28		#3
hmasenger Senior Member hamed Join Date: Apr 2009 Posts: 148 Rep Power: 17	would you pleas give me a sample,link,key words or something that could guide? i have no idea how to modify discretized equations and source terms defined in CFX.

January 28, 2014, 17:32		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	Read the documentation on source terms. The convection coefficient approach is simply the convection boundary condition. You might also be able to do this using a thermal resistance on the interface. All of this is explained in the documentation.

January 28, 2014, 17:42		#5
hmasenger Senior Member hamed Join Date: Apr 2009 Posts: 148 Rep Power: 17	tnx i will check that out