[adi10]

Hello all,

I have a small query regarding 3D modeling in FLUENT. If we have two fluids (water and air) separated by a tube wall and we want to have heat flux profile on that wall as well, then what should be the correct boundary condition for the wall. I have attached a small figure for understanding as well. It is a 3d model with tube diameter 15mm and length of tube is 100mm. The thickness for tube is taken as 1mm in fluent boundary settings.

So after modelling this geometry, I obtain a shadow wall between the fluids which is automatically coupled. Now, shadow walls offers 3 option for boundary conditions (heat flux, temperature and coupled). As per some of the answers given in CFD and ANSYS forum, one should take coupled boundary condition by giving input as heat generation rate (W/m3) and thickness value. So currently I have only heat flux values (W/m2) only and I am unable to understand how to correlate it with heat generation rate (W/m3).
If I give heat flux profile to the shadow wall and tube wall both, then heat flux gets equally divided between air and water. I am not sure whether that is a right approach or not.



Hoping for some solution to solve this issue.

[AlexanderZ]

your picture is not readable, nothing is possible to understand from it

anyway, heat generation rate (W/m3) and thickness value for wall between the fluids is the way for you . Apply heat flux value (W/m2) which you have into heat generation rate (W/m3) and define thickness value equal to 1 (m)

As you have heat flux values (W/m2) you may know the actual heat (W) because m2 is area of your wall contacted with fluid. Applying same heat (W) to volume you should get same output