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sbeckersmrt
Posts: 9
Registered: ‎01-10-2013

Issues with airflow not showing in simulation, basic room airflow modeling

134 Views, 4 Replies
03-26-2013 04:48 PM

I am new to the software. Working on a clean room space with ceiling air supply and chemical hoods exhausting the air. The ceiling supply grilles  I have setup with air as a material set as variable and an assigned flow rate and temp. The exhaust portions of the model are setup as air set as variable with a 0 psig pressure. The interior of the room is a closed space with that air volume set as variable as well. When I run the model there is no air flowing from the supply grilles and the 0 psig return grilles have velocity vectors that face into the space.

 

Any ideas? I am sure its just something simple that I have setup wrong.

 

Thanks

Stephan

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wildej
Posts: 934
Registered: ‎08-25-2011

Re: Issues with airflow not showing in simulation, basic room airflow modeling

03-27-2013 03:33 AM in reply to: sbeckersmrt

Hi Stephan,

 

To confirm:

 

All air volumes are connected to one another and set to air?

All air volumes are meshed?

All Boundary Conditions (BC's) are applied to the external boudnaries of the domain, where air enters/exits the model yes? (We cannot have internal surface BC's)

How many iterations are you running for?

If you are running forced convection and natural convection will have minimal effect there would be no need to run with air_variable - this only comes into play when you have internal heat gains/losses and a low flow rate (less than 1m/s or so and you would also need gravity on).

 

Kind regards,

Jon



Jon Wilde
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Active Member
sbeckersmrt
Posts: 9
Registered: ‎01-10-2013

Re: Issues with airflow not showing in simulation, basic room airflow modeling

03-27-2013 06:22 AM in reply to: wildej

Thanks for the reply, I am think my issue is some of my boundary conditions are not external. I am fixing that now and about to run it again.  I have been using 100 interations, dose that seem reasonable for a room airflow model?

 

Thanks again