[Getdp] Re-2: ... two disjoined bodies with radiation interaction ...

Mon Apr 10 17:13:36 CEST 2006

Dear Matt,

oops, it was pure nelgigence not to respond in public. It's not fair and definitely not wise to open a side channel for communication.

Sure, I am still interested. I have not been successful with integral quantities, as well. I vaguely recall trying to calculate the total heat flux through a rod with fixed tepmeratures at the ends. But I could not get it neither from global nor from integral quantities. Your problem seems to be related or even similar. If you like to share your files I would be glad to keep the discussion going. But unfortunately I have no solution ready.

Best regards

Matthias A. Fenner

Omicron
NanoTechnology GmbH

Limburger Straße 75 
D-65232 Taunusstein

+49 6128 987-277   Phone 
+49 6128 987-33277 Fax 
+49 6128 987-32277 Voice 

eMail m.fenner at omicron.de 
WWW.omicron.de

-------- Original Message --------
Subject: Re: [Getdp] ... two disjoined bodies with radiation interaction ... (10-Apr-2006 15:49)
From:    mkoch at gvtc.com
To:      m.fenner at omicron.de

> Hi Matthias,
> 
> thank you kindly for your response. It is encouraging to see interest in 
> this
> topic. I noticed that your response did not copy getdp at geuz.org - was that
> accidental or intentional? I would think keeping the group in the loop
> enhances
> chances for success. The e-mail traffic might also catch Christophe's
> attention,
> and his input is probably critical, I think, in these early stages?
> 
> Anyway, to answer some of your questions, I have dealt with radiation 
> exchange
> problems extensively in the past, and the configuration factor approach in 
> my
> view is preferable over the ray tracing approach - if the problem is
> sufficiently limited in scope. I am not at all concerned about this aspect
> right now, and I am also not envisioning a grand scheme that automatically
> considers these factors in all possible geometries.
> 
> I am perfectly happy to hand-code the configuration factors for now. My
> problems
> are usually relatively confined, so this would work just fine for me.
> 
> My true challenge has to do with GetDP and its treatment of quantities and
> equations and such. Right now, for example, I am not even trying to do
> configuration factors. I am just trying to have one surface heat another 
> via
> their average temperatures (using "Integral" quantities) and a fake heat
> transfer coefficient between them, and I can't even get that to work.
> 
> If you are still interested, I can send you what I have thus far so you
> can more
> easily understand where I am stuck at. Once we cross that hurdle, I think
> configuration factors and integrals would be the next step.
> 
> I like your comment about setting this up as a network problem. But
> like you, I
> have no clue as to how to go about this. Plus, I wonder if network 
> constraints
> are 0-dimensional, i.e. can only connect points, not surfaces?
> 
> If you agree, I would also like to forward your response and this e-mail to
> getdp at geuz.org.
> 
> Thanks and Regards,
> 
> Matt Koch
> mattkoch at scitex.us
> 978-726-4202
> 
> 
> ----- Message from m.fenner at omicron.de ---------
>     Date: 10 Apr 2006 08:25:18 UT
>     From: m.fenner at omicron.de
> Reply-To: m.fenner at omicron.de
> Subject: Re: [Getdp] ... two disjoined bodies with radiation interaction ...
> .
>       To: mkoch at gvtc.com
> 
> 
> > Dear Matt,
> >
> > since I sometimes have to deal with heat transfer problems I'd really
> > be interested in a solution for the radiation problem. I have no idea
> > how to attack this in a general framework in getDP just using the
> > geometry and formulation. It sounds like a ray tracing problem.
> >
> > An approach from the analytical side is to calculate configuration
> > factors between the two surfaces which are tabulated for a few
> > spacial cases. I wonder if one could use the network constraints to
> > couple two surfaces via configuration factors. I have not played with
> > network constraints yet so I am not sure this is viable at all. And
> > then it is not quite what we want since it implies special knowledge
> > and assumptions on the geometry, homogeneous temperature of the
> > surface for instance. Just placing the surfaces in the .geo file and
> > solve a radiation problem would be nicer.
> >
> > Have you made any progress in this direction?
> >
> >
> > Best regards
> >
> > Matthias
> >
> >
> >
> > Matthias A. Fenner
> >
> >
> > Omicron
> > NanoTechnology GmbH
> >
> > Limburger Straße 75
> > D-65232 Taunusstein
> >
> > +49 6128 987-277   Phone
> > +49 6128 987-33277 Fax
> > +49 6128 987-32277 Voice
> >
> > eMail m.fenner at omicron.de
> > WWW.omicron.de
> >
> >
> > -------- Original Message --------
> > Subject: [Getdp] ... two disjoined bodies with radiation interaction
> > ... (04-Apr-2006 16:32)
> > From:    mkoch at gvtc.com
> > To:      m.fenner at omicron.de
> >
> >> Hello All,
> >>
> >> I am still trying to figure out how to formulate a "long-range" problem.
> >>
> >> I have two disks that are not connected, arranged much like a capacitor.
> >>
> >> The top disk is being heated, e.g. by a volumetirc heat source, the
> >> bottom disk
> >> is not. I want the top disk to transfer some of its heat to the bottom 
> disk
> >> by
> >> radiation.
> >>
> >> The typical radiation setup in the examples radiates into free space,
> >> but not to
> >> another body, whose temperature can also change. A body to body 
> radiation
> >> problem instead involves configuration or view factors, as well as
> >> temperature
> >> integrals - the details of which are somewhat secondary until I get the
> >> overall
> >> structure of the problem right.
> >>
> >> If there is anyone out there who can help me set this up, I would much
> >> appreciate it. If there is someone, I can share with them what I have so
> >> far,
> >> which will also make the problem more clear. My goal is to solve this
> >> problem,
> >> of course, but I think it could also make for an intersting addition to 
> the
> >> examples.
> >>
> >> Regards,
> >>
> >> Matt Koch
> >> mattkoch at scitex.us
> >> 978-726-4202
> >>
> >>
> >> ----------------------------------------------------------------
> >> This message was sent using GVTC's Webmail System.
> >>
> >>
> >> _______________________________________________
> >> getdp mailing list
> >> getdp at geuz.org
> >> http://www.geuz.org/mailman/listinfo/getdp
> >>
> >>
> >>
> >> To: getdp at geuz.org
> >
> >
> 
> 
> ----- End message from m.fenner at omicron.de -----
> 
> 
> 
> ----------------------------------------------------------------
> This message was sent using GVTC's Webmail System.
> 
> 
> 
> 
> To: m.fenner at omicron.de

To: mkoch at gvtc.com
Cc: getDP at geuz.org