Transient convection heat transfer - no temperature change during cooling

NGSolve
1

Dear all,

First time using NGSolve having implemented a small convection problem. A rod is cooled via heat convection at a heat exchanged coefficient h = 131 W/m^2K.

It seems that the model is not responding as expected as the temperature remains at the initial temperature T_0 = 300 K. The infinite temperature is 77 K (T_inf) for the convective term.

I am joining the code. It saves the data in VTK format. The library matplotlib is required to get the plot of the temperature at the center of the rod.

Best regards,

Frederic

thermalmodel.py (4.5 KB)

2

Hi Frederic,
with dirichlet=“cableside” you fix the temperature at the cylinder mantle to the initial temperature. but at the same time you add a robin type boundary condition (which is then not seen) as convection.

And your source is 0 so thats why nothing happens.

best
Christopher

3

Dear Christopher,

You are right, I left the Dirichlet boundary condition. I overlooked it.

I have fixed it by removing the Dirichlet boundary condition in the definition of the finite element space (line 106 in the code) and now it is works as expected!

Thanks for the quick reply,

Best

Frederic