Measure of Heat Flux on a surface
 

Hello CFD users,

I have a question about measuring the heat flux / heat loss through a surface in a 3D model.

I try to simulate a PCM melting in a water tank in transient simulation.
I have 2 domains: Water and pcm
The interface Water/PCM is a thin layer of steel, represented by a wall boundary condition, with a shell conduction of 1 thin layer of steel.
My process duration is 3hour, so I choose a 10 Sec time step.

To measure the heat flux thought the interface I use a report file with: Report type = Facet Average, Field Variable = Total Surface Heat Flux, Surface = my interface Water/PCM


My questions are:

Is my method a good way to estimate the heat flux trough the interface Water/Pcm?

What is the unit of the heat flux measure? In fluent I see that heat flux is in W/m², but if I have selected the entire surface in the report file, does it show me the average heat flux per m² of that surface (Watt/m²), or the average heat flux on the entire surface (in Watt)?

Finally, as I work with a 10 Sec time step, and fluent write the report file each step, does the measure is the average heat flux for the 10 seconds time period or the heat flux of the 10th second?

I hope that will understand what I'm trying to do.

As a French engineering student, I am not an expert in CFD and not so good at English, so sorry for that.

Thanks,

Best regards,

Mathieu C