Fluent 6.3: how to plott Local Nusselt number using Fluent ?

lbmagis · February 21, 2014, 16:08

Hello everyone,
I 'd like to ask you the way to plott local nusselt number using Fluent 6.3 Ansys
Thank You so much in advance

farzadpourfattah · February 21, 2014, 16:39

hello.
plot>wall flux>nusselt number.
first set effective length in reference value because Fluent use this length nu number calculation.(hL/k)

lbmagis · February 21, 2014, 17:12

Quote:

Originally Posted by farzadpourfattah

hello.
plot>wall flux>nusselt number.
first set effective length in reference value because Fluent use this length nu number calculation.(hL/k)

Thank You Farzad,
well i have here: plot>wall fluxes>surface Nusselt Number
i set effective length as you said (heated wall) and plot but didnt get it,
more informations please
thank You

farzadpourfattah · February 21, 2014, 17:16

what is your mean: "i dont get it?"

lbmagis · February 21, 2014, 17:20

Quote:

Originally Posted by farzadpourfattah

what is your mean: "i dont get it?"

i dont get the right result for the local nusselt number graph

could you give more details please step by step if you want

farzadpourfattah · February 21, 2014, 17:25

if trend of Nu number is valid with experiment data but this value was wrong i had experience this problem.the length in reference value is cause of your problem.check this value and be sure form this value is calculate correctly.

lbmagis · February 21, 2014, 17:37

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TimberJ3 · February 25, 2014, 09:03

Hi

I have had this very same problem this week with this simple exercise:

2D flow inside a cylidric pipe, L=10 (SI units for all); internal_radius=0.15; external radius=0.20 (aluminium pipe) with constant heat flux in the wall (2000), a symmetry BC, a velocity inlet and pressure outlet.

I want to compare the Nusselt number obtained with Colburn's correlation. The doubt is, which reference numbers should I use? when using Area 3, Depth= 10 and length = 0.30 (hidraulic diameter for Nu=h*L/D) i just got the double, but 0.15, the radius, it feels like cheating for me.

Thank you in advance

ghost82 · February 25, 2014, 11:39

Hi,
by definition, for internal flows in pipes the characteristic length is the hydraulic diameter.

Nusselt is h*L/k not h*L/D.
Make sure to calculate correctly the heat transfer coefficient (check the reference temperature).

February 21, 2014, 16:08	Fluent 6.3: how to plott Local Nusselt number using Fluent ?	#1
lbmagis Member amine Join Date: Jun 2012 Posts: 65 Rep Power: 14	Hello everyone, I 'd like to ask you the way to plott local nusselt number using Fluent 6.3 Ansys Thank You so much in advance

February 21, 2014, 16:39	hi	#2
farzadpourfattah Member farzadpourfattah Join Date: Mar 2013 Posts: 41 Rep Power: 13	hello. plot>wall flux>nusselt number. first set effective length in reference value because Fluent use this length nu number calculation.(hL/k) lbmagis likes this.

February 21, 2014, 17:37		#7
lbmagis Member amine Join Date: Jun 2012 Posts: 65 Rep Power: 14	okkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk Last edited by lbmagis; February 22, 2014 at 17:21.

February 25, 2014, 09:03	Same nusselt number problem	#8
TimberJ3 New Member Juhti Join Date: Feb 2014 Location: Spain Posts: 4 Rep Power: 12	Hi I have had this very same problem this week with this simple exercise: 2D flow inside a cylidric pipe, L=10 (SI units for all); internal_radius=0.15; external radius=0.20 (aluminium pipe) with constant heat flux in the wall (2000), a symmetry BC, a velocity inlet and pressure outlet. I want to compare the Nusselt number obtained with Colburn's correlation. The doubt is, which reference numbers should I use? when using Area 3, Depth= 10 and length = 0.30 (hidraulic diameter for Nu=h*L/D) i just got the double, but 0.15, the radius, it feels like cheating for me. Thank you in advance

February 25, 2014, 11:39		#9
ghost82 Senior Member Rick Join Date: Oct 2010 Posts: 1,016 Rep Power: 27	Hi, by definition, for internal flows in pipes the characteristic length is the hydraulic diameter. Nusselt is hL/k not hL/D. Make sure to calculate correctly the heat transfer coefficient (check the reference temperature). TimberJ3 likes this.

February 21, 2014, 17:16		#4
farzadpourfattah Member farzadpourfattah Join Date: Mar 2013 Posts: 41 Rep Power: 13	what is your mean: "i dont get it?"

February 21, 2014, 17:25		#6
farzadpourfattah Member farzadpourfattah Join Date: Mar 2013 Posts: 41 Rep Power: 13	if trend of Nu number is valid with experiment data but this value was wrong i had experience this problem.the length in reference value is cause of your problem.check this value and be sure form this value is calculate correctly.

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