Hi,

You can select six kinds of wall BC in Fluent (thermal tab):

1. Heat flux (if you know exact the amount of heat flux through wall, e.g. 5% of heat rxn heat ...)

2. Temperature (if you know exactly temperature of the wall, e.g. in heat exchanger, you have to fix the T_c and T_h)

3. Convection (if you wanna mimic the real convection. Here you have to know the HTC, and free stream temperature)

4. Radiation (for high temperature and emission gases, you need to know the emissivity and external radiation temperature)

5. Mixed (you can set up the mixed heat transfer including convection and radiation)

6. Via system coupling (if you simulate the two domain with different model. E.g. in tubular reactor, reactions takes place in catalyst zone while the cooling stream is simulated for surrounding space)

Steps for setup those BC: Energy: on -> Wall material setting -> Boundary conditions -> Select wall BC -> Go to thermal tab.

Thank you dear Son :)

Hi,

It is not possible to define heat flux and convection for a wall at the same time in fluent. You have two options:

1. You have to use UDF.

2. You can define a thin volumetric zone instead of the wall and set one side of the zone as insulation with zero heat flux and the other face having convection. Then, define a heat generation rate inside this solid region equivalent to the desired heat flux.

Thank you dear Morteza Anbarsooz Do you know sir how to write the UDF? We had another solution, the experiment had a heat source (The heat flux source). So, we included it in the domain to select the face and give it the required heat flux. But if you know how to write a UDF, it will be very helpful...

Vielen Dank !