Nusselt number

Studentdrak · March 23, 2012, 05:31

can anyone suggest me how to calculate the nusselt number from results?

I have a duct with L/D = 62 , ReD = 8100, all walls at constant heat flux. I want to cross check my results with Dittus- Boelter equation.

pl. do reply

ghorrocks · March 25, 2012, 06:28

Define a variable in CFD-Post with the equation for Nussult number. Then you can use this variable as a normal results file variable -you can plot it, get min/max, integrate it, graph it against something etc etc

pritam1688 · March 27, 2012, 09:45

i tried but not succeded in creating this varible with formula.......
please help

Studentdrak · March 27, 2012, 10:55

how did u try pritam?

what is your formula?

lffabiani · March 27, 2012, 15:06

On CFD-POST first create an expression

Example: sqrt(Velocity w^2)

and name it ("nusselt", "my expression", or whatever)

Then on variables, create a new variable (also name it as you wish) and point the "expression" field to the expression you just created.

March 23, 2012, 05:31	Nusselt number	#1
Studentdrak Member Join Date: Aug 2011 Posts: 53 Rep Power: 14	can anyone suggest me how to calculate the nusselt number from results? I have a duct with L/D = 62 , ReD = 8100, all walls at constant heat flux. I want to cross check my results with Dittus- Boelter equation. pl. do reply

March 27, 2012, 09:45	how to create variable Nussult no in cfd post	#3
pritam1688 New Member pritam gole Join Date: Oct 2011 Posts: 3 Rep Power: 14	i tried but not succeded in creating this varible with formula....... please help

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March 25, 2012, 06:28		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	Define a variable in CFD-Post with the equation for Nussult number. Then you can use this variable as a normal results file variable -you can plot it, get min/max, integrate it, graph it against something etc etc

March 27, 2012, 10:55		#4
Studentdrak Member Join Date: Aug 2011 Posts: 53 Rep Power: 14	how did u try pritam? what is your formula?

March 27, 2012, 15:06		#5
lffabiani Member Luis Filipe Fabiani Join Date: Apr 2009 Posts: 43 Rep Power: 17	On CFD-POST first create an expression Example: sqrt(Velocity w^2) and name it ("nusselt", "my expression", or whatever) Then on variables, create a new variable (also name it as you wish) and point the "expression" field to the expression you just created.