[marsa27]

Good morning,
I am interested to simulate the glass bath convective flow, where from the top I set a thermal heat flux distribution (to consider the combustion heat). While at the bottom of the bath there are some electric boost that heat for eletric induction. In CFX I would activate the electric potential model, so from the boost walls I set an electric current as inlet flux in order to have the Joule heating in the glass (by having used the appropriate glass electric conductibility and activated the total energy model). However in the heat transfer option of the boost wall what should I set? Adiabatic so that the heat enters only from the electric field or this option assumes to zero also this heat contribution?. In alternative have you some suggestion for the correct setting? For example is necessary also the magnetic vector potential model?

[ghorrocks]

What are you trying to achieve with this simulation?

If you want to know the flow in the molten glass bath then just model the heat inputs as wall boundary conditions with the know heat fluxes applied to them.

Is there a reason you want to model the electric flow and joule heating? If all which is important is the heat generated then just model it as a heat flux and do not do electrical modelling at all.

[marsa27]

Originally Posted by ghorrocks

What are you trying to achieve with this simulation?

If you want to know the flow in the molten glass bath then just model the heat inputs as wall boundary conditions with the know heat fluxes applied to them.

Is there a reason you want to model the electric flow and joule heating? If all which is important is the heat generated then just model it as a heat flux and do not do electrical modelling at all.

Because fisically the heating in reality is only for the electric induction, not for a thermal heating from the boost.

[ghorrocks]

So isn't it easier to model all the heating as heat sources and not model the electric flow?

[marsa27]

Originally Posted by ghorrocks

So isn't it easier to model all the heating as heat sources and not model the electric flow?

Yes maybe, but in many papers introduce also the electric flow. So I don't understand what use as thermal condition at the boost walls in addition to the voltage: adiabatic?

[ghorrocks]

An adiabatic wall will add no heat. You need a heat flux wall to add the heat.

[Opaque]

Be careful here with the interpretation of an adiabatic wall.

An adiabatic wall does not allow the transfer of "thermal energy". It does allow the transfer of work, electric current, and others forms as well.

A closed adiabatic system can only change its temperature because energy can get into/out of the system in other forms, for example, work. This is a textbook example from thermodynamics 101. There are two classic examples in textbooks: the paddle wheel, with a weight and a pulley, and the heating element.

Joule heating is a distributed volumetric source. If the detailed distribution is important, the electric/magnetic field must model. If the intent is to only account for the global source, a simple volumetric source can be used instead.

[jakevink]

Originally Posted by marsa27

Good morning,
I am interested to simulate the glass bath convective flow, where from the top I set a thermal heat flux distribution (to consider the combustion heat). While at the bottom of the bath there are some electric boost that heat for eletric induction. In CFX I would activate the electric potential model, so from the boost walls I set an electric current as inlet flux in order to have the Joule heating in the glass (by having used the appropriate glass electric conductibility and activated the total energy model). However in the heat transfer option of the boost wall what should I set? Adiabatic so that the heat enters only from the electric field or this option assumes to zero also this heat contribution?. In alternative have you some suggestion for the correct setting? For example is necessary also the magnetic vector potential model?

It sounds like you are simulating a complex system with multiple heat sources and different modes of heat transfer. In CFX, you can activate the electric potential model to account for the Joule heating in the glass caused by the electric boost at the bottom of the bath. Regarding the heat transfer option for the boost wall, you can set it to "adiabatic" so that the heat enters only from the electric field. This option assumes that the wall does not exchange any heat with the surrounding fluid due to thermal conduction or radiation. As for the magnetic vector potential model, it depends on the specifics of your system and whether or not magnetic effects are significant. If you are unsure, it may be worth consulting the CFX documentation or seeking the advice of a specialist in the field.