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Flow Imbalance

 
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mbwaite



Posts: 46
Location: New York, NY
PostPosted: Fri Oct 10, 2008 7:15 pm    Post subject: Flow Imbalance Reply with quote

When trying to run CFD in a simulation of a generic building I get a message in the "CFD Grid Statistics" that there is a "Flow imbalance, Inflow=423.8 CFM, Outflow=0.000 CFM." I'm not sure what would cause this. I get the same message with the same numbers whether I am trying to simulate the entire building or just one floor or zone. I have one zone with 2 CFD boundaries.

I am just beginning to play around with this. Are there plans for a help file, tutorial or other documentation?

Thanks,

Mike
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Steve Potter



Posts: 298
Location: newcastle
PostPosted: Sat Oct 11, 2008 9:48 am    Post subject: Reply with quote

Hi Mike,

When you set up ventilation boundary conditions for a model (supply diffusers and extract grilles), you need to ensure that the amount of air supplied to the domain matches the amount of air removed otherwise you will see the flow imbalance error message.

In this case it looks as if you've defined some supply (423.8 cfm) but no extract. You will need to position extracts with a defined flow rate equal to a total of 423.8 cfm.

We will be making the documentation available within the next week or so.

Regards,

Steve
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