Help: Using preCICE adaptor with own solver in OpenFOAM - Heat transfer direction is wrong!

Hi,

I am trying to use preCICE adaptor with an in-house solver in OpenFOAM. We are trying to get the steady state solution for a reacting flow where the flame is positioned above a burner plate and there is conjugate heat transfer through the plate. We have incoming fuel + oxidiser mixture at T~290K and then the combustion products at T~1890K. Most of the incoming mixture has temperature close to 290K. The initial state at t=0 is shown below. The small rectangle at the bottom right of the image is the solid part.
initial_kornilov_2022_05_11

We assume that the burner plate is initially at a temperature of 400K and we expect the heat to flow from the upper side of the plate (where the flame is located) and then heat up the incoming mixture through the side wall of the plate.

While running the simulation, we did not get any error and the coupling between the reacting solver and laplacianFoam worked fine. However, the final result gives heat transfer in the reverse direction i.e., we see that the temperature of the fluid close to wall decreases while the temperature of the solid increases.
final_fluid_cht_2022_05_11
Here, you can see a small region of cold flow close to the wall.

final_solid_2022_05_11
Also, the heating occurs on both sides of the wall, rather than having a direction of heat flow from top to the side wall (through the solid domain).

We also found that for the final time step, the T file for ‘solid-openfoam’ gave uniform value rather than a non-uniform distribution in temperature.

interface
    {
        type            fixedValue;
        value           uniform 409.1182552;
    }

If possible, could you help us in determining why the heat transfer is in the opposite direction? Perhaps, we may be overlooking something trivial?

Hi @AswathySurendran,

what fields are you coupling and with which direction?

If you are coupling temperature and heat flux, heat flux is reversed when reading: openfoam-adapter/HeatFlux.C at develop · precice/openfoam-adapter · GitHub (see the - sign in the read() function, line 98).

In our tutorials, we assume that the solid heats up the flow. I am not sure how this could be wrong in your case, but you could try reversing the direction of temperature and heat flux (Dirichlet-Neumann vs Neumann-Dirichlet).