How fluent calculate heat-transfer-coefficient?
 

Hi,
I have a simple test, a cube 1*1*0,2 (l*l*x).
Boundary condition T1=350°K in upper face, T2=300°k in opposite face, k=200.

So Q=k/x*A*(T1-T2)=50000

Fluent report flux no problem, Q=50000 as formula, but I want to export heat-transfer-coefficient for every cells. he must be 1000, but fluent calculate 1.2194E+003. Why?

For this case I insert only 1 cell mesh.

what is the bulk velocity?

Why bulk velocity?
it's a simple Heat transfer in a solid plate.

you want to check the thermal conductivity?

Heat transfer coefficient is for the convection.

Goal is http://upload.wikimedia.org/math/a/1...afc48bd8c7.png, that is conductance

isnt it obvious? As k is fixed and so is the dx

Yes, in simple case. But when I have a complex structure whit fins?
Goal is to understand how fluent calculate this rate or I can calculate this from ''fluent-export''. So I can tell: this is average http://upload.wikimedia.org/math/a/1...afc48bd8c7.png of structure from report flux. That is report flux=Q, U=Q/A/(T1-T2).
From mesh I can calculate every single Q(i) by cells, so I can compare average with single station to see the difference and if this difference is high.
Imagine a structure like this:http://upload.wikimedia.org/wikipedi...87fuselage.jpg

Delta X is changing ? K is changing? If yes then you UDF.

Only Delta x, k is constant.
how can I proceed?

In report fluent I have Heat Flow [ Watt ] (Heat Rate), that is Q for every face mesh that I call Qi, and area of mesh Ai. Whit delta Temperature I have U.
U=Qi/(Ai*delta(T))

How can I calculate this division?