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[samstudent]

Hello there,

I am simulating a natural convection heat sink within a cylinder air volume. I would like to simulate the radiation emitted by the heat sink into the open atmosphere. I have pressure outlets set up on all the surfaces of the cylinder, so air is free to flow in from anywhere.

I have seen multiple videos about radiation to wall boundary conditions but I can't find any information about how to simulate radiation into the open atmosphere or a pressure outlet.

Currently, the results without radiation look promising and the airflow field seems realistic, but I need to add radiation to obtain a more accurate result.

Any help is appreciated. Thank you.

[Nikhil Narale]

Hello,

Can you please explain what do you exactly mean by the open atmosphere? Do you want to consider the radiation effects in the fluids?
Regarding the pressure outlet, you can specify the temperature of the gas/walls beyond the outlets, or even beyond the inlets for that matter. This is helpful when the temperatures of the gas/wall beyond inlets/outlets (basically outside the computational domain) differs by a significant amount from the temperature inside the computational domain and you want to consider the radiation flux through the inlet and/or outlet boundaries. This can be done by assigning External Black Body Temperature at inlets/outlets. To know more, refer to this link and jump to '14.3.8.1.2. Black Body Temperature' section: 14.3.8. Defining Boundary Conditions for Radiation (ansys.com)
If you are unable to open the link, refer this forum discussion: Using Help with links ÔÇö Ansys Learning Forum

Nikhil