[esp-r] Re: warning messages from networks during simulation

[Nuno Fernandes]

Thanks Samuel

Let me try to answer your questions.

>1. Do all nodes have a path to external nodes (even when controls are
>active)

No, some nodes have only connections to other interior nodes, and at this
time I have no controls.

>2. Is the network illdefined (e.g. a node may have air flowing to it
>through
>some forced flow component but no means for the air to flow out from the
>node)

I do not have any kind of system its all temperature and pressure
distribution through nodes. 

>Usually it is best to draw the flow network on paper and then troubleshoot
>it.

Thanks for the tip, but as I do not have many experience with networks I
have draw the network first and than introduced it in the network and
everything look correct.
 
What do you mean with mass imbalance at a node?

What could be the problem?

Best regards 

Nuno Fernandes

 
###################################################
Nuno Tiago Afonso Fernandes
 
Universidade de Aveiro
Departamento de Engenharia Mecânica
 
nuno.fernandes at mec.ua.pt
###################################################
-----Original Message-----
From: Aizaz Aamir Samuel [mailto:aizaz.a.samuel at strath.ac.uk] 
Sent: terça-feira, 28 de Novembro de 2006 11:52
To: Nuno Fernandes
Cc: esp-r at lists.strath.ac.uk
Subject: Re: [esp-r] warning messages from networks during simulation

Nuno,

This message appears when the flow network has not been able to converge.
This
usually occurs when there is a mass imbalance at a node. Possible things to
look
for:
1. Do all nodes have a path to external nodes (even when controls are
active)
2. Is the network illdefined (e.g. a node may have air flowing to it through
some forced flow component but no means for the air to flow out from the
node)

Usually it is best to draw the flow network on paper and then troubleshoot
it.

-Aizaz

Quoting Nuno Fernandes <nuno.fernandes at mec.ua.pt>:

> Dear all esp-r users
> 
>  
> 
> I have a question related with fluid flow networks.
> 
>  
> 
> In my project I have a big zone that I have sub-divided. The contact
> surfaces between this zones (sub-divided) were set as transparent
fictitious
> constructions.
> 
>  
> 
> Them I have set an all air fluid flow networks between them and define the
> components between the interior nodes as openings corresponding to all the
> contact area between the zones.
> 
>  
> 
> However when I rum the simulator a warning message appears:
> 
>  
> 
> Please check (in the following order) that:
> 
> -          each node has some flow path to a boundary pressure and
> 
> -          iteraction convergence control is not to strict.
> 
> Day 23 Month 12 Hour 13.00 : 100 iteractions: flows solution failed 
> 
>  
> 
>  
> 
> This happens for several days months and hours.
> 
>  
> 
> Can someone explain me watts’ wrong.
> 
>  
> 
> Thanks in advance.
> 
>  
> 
>  
> 
> Best regards,
> 
>  
> 
> Nuno Fernandes
> 
>  
> 
> ################################################# 
> 
>   Nuno Tiago Afonso Fernandes
> 
>  
> 
>   Universidade de Aveiro
> 
>   Departamento de Engenharia Mecânica
> 
>   Campus Universitário de Santiago  
> 
>   3810-193 Aveiro  
> 
>   Portugal
> 
>   Tel.: +351 234 370 830
> 
>   nuno.fernandes at mec.ua.pt
> 
>   www.ua.pt <http://www.ua.pt/> 
> 
> ##########################################################
> 
>  
> 
>  
> 
>