[Solved] Thermal Cooling Simulation with Oil

Hi everyone,
I need to do a thermal cooling simulation for a transformer.

The simple model is shown as below image:

Normally, we run the simulation with water/air.

However, the fluid used in this case is OIL.
So can AcuSolve make the simulation with Oil?
If yes, Is there any special setting has to be made?
 

Furthermore, how should i define the interface b/w air and Oil (or water) in this case?
Should i use multi-phase (level set/ Euler) or free surface or any other treatment?

Thank you very much!