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## Simulation CFD

Active Member
Posts: 10
Registered: ‎04-03-2012

# air flow from one space to another space.

574 Views, 8 Replies
04-29-2012 02:22 PM

How should I set the boundaries for a flow from one space to another space in a building.

here is the volume flow, a fixed data

So I will remove air from one room and take it to the other room.

I like to hear it

best regards

Mark ﻿

Employee
Posts: 60
Registered: ‎04-06-2011

# Re: air flow from one space to another space.

04-29-2012 06:44 PM in reply to: markkolk

Hi Mark. Assuming the rooms are connected? The easiest way is to apply a flow rate on one end (the inlet) and apply an outlet boundary condition on the other end to represent a return in the system. Easiest outlet BC is a Pressure = 0 on a surface.

If this doesn't make sense, either post an image here (if you can) or a "share" file (File>save>share file)

Active Member
Posts: 10
Registered: ‎04-03-2012

# Re: air flow from one space to another space.

04-29-2012 11:04 PM in reply to: markkolk

The drawing is a sectional view of the building, it is a building in a building. like a box in a box.(see Attachment)

the air inlet from the floor and the air outlet in the wall.
the model is made in revit and read into CFD 2012, I have two mass placed. 1 in the inner sanctuary building and 1 in the entire building. these two overlap each other.

I want to simulate air flow between these two. under the influence of solar radiation and temperature outside.
How should I set my boundaries. what happens to the two mass which overlap and are set to air.

I like to hear it,

Sincerely,
mark

Employee
Posts: 60
Registered: ‎04-06-2011

# Re: air flow from one space to another space.

04-30-2012 03:46 AM in reply to: markkolk
Hi mark.. The air needs to exit or vent somewhere. Otherwise, the space would just build infinite pressure as air is added
Active Member
Posts: 10
Registered: ‎04-03-2012

# Re: air flow from one space to another space.

04-30-2012 06:24 AM in reply to: markkolk

hi derek,

In order to get air out of the building, I have a hole at the bottom, and holes made ​​in each floor in the model. in this way, the air can leave the building.

but how do I set my boundaries for this, just the flow or by  pressure and flow.

best regards
Mark

Employee
Posts: 60
Registered: ‎04-06-2011

# Re: air flow from one space to another space.

04-30-2012 07:49 AM in reply to: markkolk
You only want one flow/pressure bc on each. Flow rates on inlets, PRES=0 on outlets. P=0 signifies atmospheric pressure.
Active Member
Posts: 10
Registered: ‎04-03-2012

# Re: air flow from one space to another space.

04-30-2012 07:56 AM in reply to: markkolk

Thanks so far,

I will try it, and let you know if it worked.

greet

Mark﻿

Employee
Posts: 60
Registered: ‎04-06-2011

# Re: air flow from one space to another space.

04-30-2012 08:01 AM in reply to: markkolk
Depending on how sensitive the info is, often if you post the *.cfz file, someone might be able to tak a quick look if you run into trouble
Active Member
Posts: 10
Registered: ‎04-03-2012

# Re: air flow from one space to another space.

05-07-2012 09:32 AM in reply to: markkolk

Hi

I let the model solve, but in the end it does not go feather. If do a 100 iterations it stops at 99 and if i
do 300 iterations if I stop it at 299.

what can this be?

Best regards,

mark﻿