Greetings guys,
I have been using Fusion to design and run thermal simulations for a project I am currently working on and I need your help to clarify some things about the thermal simulation, as well as whether what I am planning to do can be simulated in Fusion, or whether I should instead use Nastran.
Below you can see a simplified version of my geometry. Basically, it is a 3U CubeSat (2U being the red box, 1U the green box) interfacing with the launcher's surface (yellow geometry) on top of which the cubesat is mounted. The idea is that I assign fixed boundary conditions (in terms of temperature) to the yellow block, perform the thermal simulation and observe the behaviour of my system (particularly the internals). Of course, there are going to be more components added inside the box at a later time.
The base assumption is that the outer surfaces have perfect MLI insulation, hence, they don't radiate or interact with the space environment. The red box is going to be a pressurized vessel and will have gas, which will be circulated around through forced convection applied by a fan. Inside the red and green boxes, it is expected to have radiation by the inner surfaces and the components that will be added later in the assembly.
You can see a cross section of my geometry below:
There are a few questions I have regarding that, and I would greatly appreciate if someone from Autodesk could clarify my queries:
1) When setting up a thermal simulation and using "Radiation" or "Convection" loads, it asks me to input an ambient temperature. My question is the following then: If I select only the internal walls of, say, the red box, and add a radiation and convective load, does it mean that the software simulates an atmosphere with a certain ambient temperature for the selected surfaces inside the box only, meaning that the outside surfaces of the assembly are still in vacuum? Or are these ambient temperatures creating an atmosphere around the whole assembly?
I hope my question and description is clear enough, otherwise let me know to rephrase.
2) My second question has to do with some limitations I have noticed in the simulation and whether you would advise to use Nastran instead to achieve the desire effect:
As explained in my intro, I am interested in examining the thermal behaviour of the system (specifically the internals). The outside will be perfectly insulated and in vacuum condition. The inside of the red box will be a pressurized vessel with gas, and will experience all 3 thermal loads: conduction, forced convection and radiation. The inside of the green box will just experience conduction and radiation. Right now, I have noticed that cooling caused due to forced convection cannot be simulated in a "thermal study", only in "electronics cooling" study, which, in turn, appears to have some limitations as you cannot set radiation loads there.
My question is, do you think the above scenario can be simulated in Fusion at all, or should I save myself the trouble and go straight to Nastran to do these thermal simulations?
I would greatly appreciate your advice. Thank you very much for your time. If you need a further clarification, please let me know.
Kind Regards,
Kon
