Nusselt number in tube
 

Hi all

I want to calculate Nusselt number in a tube.... I use the heat transfer coefficient provided by Star

Nu= hcoeff * D/K

but I didn't get the right solution.

Any hints.

Thanks alot

Re: Nusselt number in tube
 

hcoef seems ok, did you check your TBulk temperature?

Re: Nusselt number in tube
 

Thanks alot.

I have checked that. I have used T_bulk=Sum(T*u)/Sum(u), the sum goes all over the fluid cells. but It didn't give the right answer in comparison with the analytic solution.

Shall I multiply the h_coeff with the circumfincial area (2 Pi D)? or else.

Ahmad

Hi guys!

My case is very simple , its laminar flow in a pipe with constant wall temperature. I take the length as long as the flow can reach to fully thermally and Hydrodunamically developed. When I get the Nusselt Number from the xyplot/Surface Nusselt Number it can seemed that the Nu begins from a large number(as predicted by theory) and go toward zero at the end of pipe (the theoric value is 3.66). Can anybody help me?
I can send my case to you for more information.

Thanks alot
.