I am currently experiencing some confusion over the setting of my sub-domain boundary condition. My initial questions were mention over at another thread which can be found here.

My aim is to model a tunnel dimensions 150m long 10m wide 8m high, with a localize heat source model as a void in the picture below.
The geometry have been split using workbench geometry and suppressed before meshing.

My idea is to replace the "fire" as a heat source.

Is it require to model a solid geometry in place of the void as shown in the picture below. This would enable me to create a solid Domain and define a sub-boundary condition where i can input the heat source parameters.

Initially i have tired creating a sub-boundary vie the fluid Domain by picking the surfaces along the void. But in this case, does that means that the "sub-boundary" which is base on the fluid is releasing the heat instead?

1) Model the sub-domain as a fluid region and apply the heat source as a volumetric heat source. This way you will model fluid flow in the sub-domain region.
2) Don't use a subdomain and remove it from the mesh. Then apply the heat source as a boundary condition on the faces. This way you do not model the fluid flow in the sub-domain region.

Your choice.

Flaky

October 7, 2010 06:51

Quote:

Originally Posted by ghorrocks
(Post 278238)

You have two choices:

1) Model the sub-domain as a fluid region and apply the heat source as a volumetric heat source. This way you will model fluid flow in the sub-domain region.
2) Don't use a subdomain and remove it from the mesh. Then apply the heat source as a boundary condition on the faces. This way you do not model the fluid flow in the sub-domain region.

Your choice.

Hi ghorrocks,

Thanks for your reply.
Correct me if i have interpreted your advice wrongly.

The Domain being the Fluid and the sub-boundary created would be considered as boundaries on the Fluid itself. For Sub-domain created that would still be model as a fluid region. Thus for options one which u stated it would be a heat transfer from the fluid.

I am looking for a "fire" heat source region to transfer the heat to the fluid. Therefore currently my fire region which is a void as shown above only has surfaces sharing with the fluid region. So my choice has to be option 2?

ghorrocks

October 7, 2010 07:10

If you have set the sub-domain as the same material as the main domain then the sub-domain is merely a region you can apply stuff to - in your case a volumetric heat source.

I have no idea what you final sentence means but the difference between my two options is whether you model the fluid flow in the sub-domain or not. Both methods will work fine.

Flaky

October 7, 2010 07:33

Quote:

Originally Posted by ghorrocks
(Post 278250)

If you have set the sub-domain as the same material as the main domain then the sub-domain is merely a region you can apply stuff to - in your case a volumetric heat source.

I have no idea what you final sentence means but the difference between my two options is whether you model the fluid flow in the sub-domain or not. Both methods will work fine.