Computing heat flux across interface boundary

[JuliaHLee]

Dear MOOSE experts,

I have a transient heat transport model consisting of the porous media Navier-Stokes module coupled with the HeatConduction module. My solid block is embedded inside the porous media and it is separated from the porous media by interface boundary (sideset). While I have the advective diffusive heat transport in the porous media, I would like to compute heat flux [W/m^2] from the porous media to the solid through the interface boundary for each element. Is there a specific object for this? Also, is there a way to get the temperature for each element at the interface boundary?

It would be great to have any information regarding that. Many thanks in advance.

Best regards,

Julia

[GiudGiud]

Hello

I would like to compute heat flux [W/m^2] from the porous media to the solid through the interface boundary for each element

For each element I would use the SideDiffusiveFluxAux on the solid side to save this quantity into an axuiliary variable with a boundary restricted auxkernel.

While I have the advective diffusive heat transport in the porous media

Is there any advection from one phase to the other though? I imagine there is only diffusion at the boundary, with no-slip boundary conditions.

Also, is there a way to get the temperature for each element at the interface boundary?

You can use a boundary restricted auxkernel to save the wall temperature onto an other auxiliary variable.
Or you can use this sampler to save it to a file
https://mooseframework.inl.gov/source/vectorpostprocessors/SideValueSampler.html

[GiudGiud]

The modified auxkernel is in a PR here:

This should let you achieve:

Also, is there a way to get the temperature for each element at the interface boundary?

For

I would like to compute heat flux [W/m^2] from the porous media to the solid through the interface boundary for each element. Is there a specific object for this?

You were looking at DiffusionFluxFVAux but it s using the cell values for the flux.
You might want to do the same thing as the ParsedAux to get the boundary values for the flux

[JuliaHLee]

Thank you very much for the implementations and updates! I found the page regarding this issue on the Pull Requests (PR).

But after I updated moose, I still don't see the added files and the changes in ParsedAux codes. Does it mean that those changes are still not applied in moose repository?

[GiudGiud]

the PR has not been merged. you have to check out that specific branch if you want to use this code, not the main devel or master branch

[JuliaHLee]

Thanks a lot for the implementation! With the code, I can compute the face value of the variable in the porous media block.

But I still could not get the face value from the solid block. When I placed the variable of the solid block for the ParsedAus, the simulation gets terminated. Before you mentioned that it should be possible to get the face value of the variable in the solid block:

And does it also allow to get the face value from the variable, which belongs to the solid phase?

Yes that can be done too. Functors are a base class of both finite volume and finite element variables, so the same code applies

Could this happen due to the boundary (created by "SideSetsBetweenSubdomainsGenerator") attached only to one block?

Also could you please give more clue about computing heat flux at the boundary using ParsedAux? You mentioned:

You might want to do the same thing as the ParsedAux to get the boundary values for the flux

For that, should I manually provide an equation for the ParsedAux?

[GiudGiud]

Could this happen due to the boundary (created by "SideSetsBetweenSubdomainsGenerator") attached only to one block?

ah yes we will only support evaluating on the side that the functor is defined on

You might want to do the same thing as the ParsedAux to get the boundary values for the flux

By that I mean evaluating functors. You can compute face gradients with functors

For that, should I manually provide an equation for the ParsedAux?

Is your flux advective? If so an equation might work. We dont support gradients in parsed expressions at this time