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-   -   Nusselt and refrence values (http://www.cfd-online.com/Forums/fluent/34051-nusselt-refrence-values.html)

avesta June 27, 2004 03:31

Nusselt and refrence values
 
hi all All books on heat transfer tell me the Nusselt number of the fully-developed laminar flow in a pipes is a constant;if the wall temperature is constant,the Nu=3.66;if the heat flux is constant,the Nu will be 4.36. but when i simulate this ,Nu in constant wall temperature will be 2.59 and it do not limit to 3.66 in fully developed laminar flow. i do not know what reference values put in meno of reference valuen in report>reference values... what reference values do you recommand? i want to simulate laminar flow in a pipe as non-dimentional by Fluent? inflow: U=1,T=1 WALL: U=0, T=1 Density=1, Cp=1, Thermal Conductivity(K)=1/(Re.Pr), Viscosity=1/Re guide me best regard Avesta

ZenCef May 18, 2010 17:42

Hi guys,

I have the same problem. I couldn't confirm the nusselt number of the fully developed laminar flow in a pipe. I compute from inlet in referance values and i change the length with hyd diameter, temperature with the bulk temp which i compute from volume integral-mass average-static temperature.

Please help me to confirm. Sincerely yours...

Kalendar May 19, 2010 10:15

Nussult number
 
Hi Avesta,

To get the Nussult number:
1. Report the total heat transfer for the wall (from report menu)
2. Divided by the wall area to get the Fluxes which is equal to Nusselt number if you use non-dimensional form correctly.

Good Luck
Kalendar


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