I am just simulating a three cubes one inside another to emulate the heat transfer between an aluminium cast piece at 600ºC (nucleus, smallest cube) and the mould structure (second cube) and the aire (the biggest one that are an enclosure).
I don’t know why the heat transfer in my simulations (Run 1.2 - 1.5; 2.1 and 3.2) stops at any moment and it doesn’t expands throughout the structure of the mould and heat the air. As you can see, I’ve made simulations with different end times but it happens in every one.
I have selected Transient Conjugate Heat Transfer because the simulations works by fluid (air) and a solid (mould and the cast considering it has been solidified yet) and the boundary condition of the cast is a table that decreases the temperature from 600 to 250 ºC in 1000 s. I’ve created an initial conditions of a cartesian box for the smallest cube (cast) at 600 ºC and a velocity for the air at 1 m/s in Y axis.
I know that the boundary conditions have to be a Wall for the mould with a variable value in a table (like I’ve explained above), Natural convection for the biggest cube representing the air volume and I think I should have the Wall with a fixed heat flux boundary condition but if I set that a multiple boundary condition error appears.
What could be the problem?