[esp-r] Re: Zero Stack Pressure

[Achim Geissler]

Hi Mostapha

looking at your .afn, I think the problem is that all your connections  
to external nodes are in one zone (01).

To get an afn up and running, a basic requirement is that for every  
zone you can go from an external node to a zone ... to >the< zone ...  
to a zone ... and so on and then to a (different) external node again.  
I think this does not hold for your afn. Add a connection type "tiny",  
e.g. a crack a factor 10 or 100 smaller than your _crk types and  
connect the lowermost zone(s) to an additional external node.

Then something should happen and there should be pressure differences.

Best
Achim




On Jun 9, 2010, at 2:47 PM, Mostapha Sadeghipour wrote:

> Hello Aizaz,
>
> I think the problem is not the node heights in my case, however I'm  
> not sure. The .afn file is attached.
>
> Regards,
>
> Mostapha Sadeghipour
>
> On Wed, Jun 9, 2010 at 3:54 PM, Aizaz Samuel <aizaz.a.samuel at strath.ac.uk 
> > wrote:
> Look up how node heights are defined in exemplars>network
> ventilation>alternative facade vent.....
>
> Theory can be found in Jan Hensen's thesis (section 4.3.2) available  
> at
> http://www.esru.strath.ac.uk/publications.htm
> --
> Dr Aizaz A Samuel
> Department of Mechanical Engineering
> University of Strathclyde
> M324 James Weir Building
> 75 Montrose Street
> Glasgow, UK
> G1 1XJ
>
> T:+44 141 548 5765
> F:+44 141 552 5105
>
> On Wednesday 09 June 2010 11:28, Mostapha Sadeghipour wrote:
> > Dear esp-r users,
> >
> > I'm modeling an atrium with a closed glass roof. The atrium has  
> nearly 16m
> > height and it only connects to the outside through 3 cracks on the  
> roof. I
> > divided the atrium into 5 vertical zones, and adjacent vertical  
> bypass
> > zones. They are connected to each other through fictitious faces.
> >
> > Common orifice components connect zone nodes to each other  
> vertically, and
> > door component connects zone nodes to bypass nodes horizontally. The
> > attached image shows the Air Flow Network in my model more clearly.
> >
> > I supposed that esp-r includes the stack effect whenever delta  
> height
> > between the nodes and the component is not zero. So I expected to  
> have a
> > stack pressure in the vertical connections. But when I check the  
> results
> > the stack pressure in the connections are zero!
> >
> > I'm also curious how esp-r consider the stack effects and the  
> gravity? The
> > components dP are set manually and there is no "g" in the  
> equations? Where
> > I can find the PSTACK equations that is used to calculate DP:
> > DP=PRES(IDPS)-PRES(IDNE)+PSTACK(ICNN).
> >
> > Thanks in advance.
> >
> > Mostapha Sadeghipour
>
>
> <atr.afn>_______________________________________________
> esp-r mailing list
> esp-r at lists.strath.ac.uk
> http://lists.strath.ac.uk/mailman/listinfo/esp-r

achim.geissler at intergga.ch




-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.strath.ac.uk/archives/esp-r/attachments/20100609/3c9df90e/attachment.html