[vitor]

I'm trying to simulate simple steady heat transfer between the wall of a pipe and the water flowing inside it. The case is very simple, I have a velocity and a temperature for the inlet and I wish to know the average temperature at the outlet.

I'm setting these BCs:

Velocity

Inlet: fixedValue (0 0 0.05);
Outlet: zeroGradient;
Wall: fixedValue (0 0 0);

Pressure

Inlet: zeroGradient;
Outlet: fixedValue 0;
Wall: zeroGradient;

Temperature

Inlet: fixedValue 300;
Outlet: zeroGradient;
Wall: fixedValue 500;

I first tried using buoyantBoussinesqSimpleFoam, since the flow is incompressible and steady, but it's diverging. Which solver should I choose? Any advices??


Thanks in advance,

BR,

Vitor.

[m.nichols19]

I recently solved this problem, but with air flowing through the pipe instead of water. I used the buoyantSimpleFoam solver.

best regards,
Matt

[vitor]

Hey Matt,

thank you for your reply. I've managed to complete the simulation, but the results are not what I expected, I mean, the temperature at the outlet is lower then it should be (if anybody has any what could be the causes, please enlighten me).

Can anybody explain to me how the code knows the thermal conductivity of the fluid? Is it only by the Prandtl number? Is there a way to perform a simulation with a variable thermal conductivity?

[vitor]

Hi again,

I have another question. Is there a straightforward way to calculate the turbulent Prandtl Number?

I'm not very familiar with this adimensional (I know it's the ratio between eddy momentum diffusivity and heat diffusivity), but I've noticed that this number plays a decisive role in the average temperature at the outlet.