I would like to simulate the performance of a vacuum jacket as an insulator

[Anonymous]

I need help understanding how to simulate a vacuum jacket around a borosilicate tube with hot gas inside.

The vacuum jacket is silvered and the vacuum level is 10e-6 Torr.

Many thanks in advance for your help.

[Marcin_Kosciolek]

Hi @Anonymous 

I am afraid it can be impossible in Fusion. Tell me please, are you only interested in the thermal aspects of the insulator you want to simulate?

[Anonymous]

Thanks very much for helping me. I deeply appreciate it.

I want to simulate a quartz tube 12mm in diameter with an 8mm ID. The tube is carrying N2 at 355C. For all practical purposes this can be treated as a constant temperature source from a simulation perspective. This tube is surrounded by a larger quartz tube that is a deep vacuum at 10e-6 Torr. 

If we assume the inside tube is a constant temp, can I simulate the heat loss per meter through the vacuum jacket?

[Marcin_Kosciolek]

Hi @Anonymous 

Ok, the issue is clear now. We need to use Thermal study in Fusion, and since we deal with a deep vacuum (I think we can assume the value 10e-6 Torr is a state, where we don't have a medium uses to transport heat) the only possible heat transfer is radiation, so in a study, you need to define only applied temperature (heat source) and radiation (heat transfer) as boundary conditions.

[Anonymous]

Does the radiation just depend on temperature, using black body radiation?

[Marcin_Kosciolek]

Hi @Anonymous 

If we are talking about a perfect black body, the emissivity is equal to 1. If we are talking about "real" materials (which have emissivity lower than 1) we should check their emissivity, because this parameter depends on the temperature (I think it will be near 1 anyway). Of course, the best way would be to read this value from the tested materials database.