car parking
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mattiperr
Feb 27, 2008, 6:30:51 AM2/27/08
to FDS and Smokeview Discussions
Hello, I'm modeling a fire in a car parking and I've some doubts about
the creation of the simulation...
1) User's Guide says (pag.40) "if you simply want to specify a fire of
a given HRR, you need not specify any material properties". I'm
studying a car burning...so, this sentence means that if I put the RHR
curve (as shown in the VTT dissertation of Prof. Mangs) in FDS,can I
simulate my fire without saying anything about the platics or metals
that compose my car?
2) If I model a car, is a good choice to divide it geometrically in
3-4 parts (i.e. passenger area, pneumatic tyres...) and to simulate
the fire or it's better to create a single surf with more materials
each with its own mass fraction?
Thank you very much
m.
the creation of the simulation...
1) User's Guide says (pag.40) "if you simply want to specify a fire of
a given HRR, you need not specify any material properties". I'm
studying a car burning...so, this sentence means that if I put the RHR
curve (as shown in the VTT dissertation of Prof. Mangs) in FDS,can I
simulate my fire without saying anything about the platics or metals
that compose my car?
2) If I model a car, is a good choice to divide it geometrically in
3-4 parts (i.e. passenger area, pneumatic tyres...) and to simulate
the fire or it's better to create a single surf with more materials
each with its own mass fraction?
Thank you very much
m.
Hostikka Simo
Feb 27, 2008, 7:33:22 AM2/27/08
to fds...@googlegroups.com
> means that if I put the RHR curve (as shown in the VTT
> dissertation of Prof. Mangs) in FDS,can I simulate my fire
> without saying anything about the platics or metals that
Yes. Only thing you need to define is the combustion reaction (REAC).
(now, please don't ask here, what is the proper reaction)
> 2) If I model a car, is a good choice to divide it geometrically in
> 3-4 parts (i.e. passenger area, pneumatic tyres...) and to
> simulate the fire or it's better to create a single surf with
> more materials each with its own mass fraction?
What do you think? Maybe you should try how it affects the simulation.
IMO, you only need a simple model of a car main body and the roof.
The flames are mostly coming out of the windows.
Few words about car park simulations:
Using the HRR curves presented in the dissertation by Mangs (peaks at
1.5 MW)
is not appropriate. Those cars are really old and don't represent modern
cars.
If you don't have better data, you could use the data from
Joyeux, D., Kruppa, J., Cajot, L.-G., Schleich, J.-B., van de Leur, P. &
Twilt, L. 2002.
Demonstration of real fire tests in car parks and high buildings. Final
report on Contract
No 7215-PP/025, 1 July 1998 to 30 June 2001. EUR 20466 EN (2002). 223 p.
Couldn't find electronic version of the final report, but a Final draft
at
http://www.iicbm.org/tech/tests/410b-PP025%20FINAL%20REPORT1.pdf
See Section 4 on modelling the HRR curves. These heat release rates go
up to 8.5 MW, and they
are from 1990's! I ques the modern cars peak easily above 10 MW. And
that is a single car.
For non-sprinkled case, ignition of neighbouring cars should be
considered as well.
Simo
johannes
Feb 27, 2008, 3:14:04 PM2/27/08
to FDS and Smokeview Discussions
There was a risk-based research on car-park fires as recent as 2004
with some interesting data:
http://www.civil.canterbury.ac.nz/fire/pdfreports/YLi04%20.pdf
Johannes
with some interesting data:
http://www.civil.canterbury.ac.nz/fire/pdfreports/YLi04%20.pdf
Johannes
mattiperr
Mar 3, 2008, 4:15:22 AM3/3/08
to FDS and Smokeview Discussions
Thank you very much for your useful suggestions. I'm an italian
student and with my professor we're testing FDS in order to use it in
the future.
Now I created a simulation and I'm beginning to have reasonable
outputs. Now I'm trying to semplify the model (because the simulation
is too slow...2 days only 250 s) and to fully understand all the data
that I can choose in the definition of the fire.
I created a model of this car parking with three car, the one in the
centre is a vent burning with the HRR of Schleich et al. (1999)
reference curve, but to create the fire for the 2 other cars (one on
the left side, the other one on the right side) I cannot use
Schleich's data, because our parking has a sprinkler system. So I've
thought to create the other 2 cars as a solid which surface has an
ignition temperature. What do you think about this way of thinking?
Reasonable? (obiouvsly I'll have to reflect about the ignition temp of
a car that it's not simple)
Another question is about the reaction. I chose POLYURETHANE as
reaction and I've some doubts for the values os Soot Yield, CO Yield
and H2 Yield. About the Soot Yield I read old discussions and I chose
a reasonable value of 0,1. In my simulation I chose also a value for
the CO and H2 Yield of 0,01 both...What do you think about these
values?
Best regards,
matteo
> > m.- Nascondi testo tra virgolette -
>
> - Mostra testo tra virgolette -
student and with my professor we're testing FDS in order to use it in
the future.
Now I created a simulation and I'm beginning to have reasonable
outputs. Now I'm trying to semplify the model (because the simulation
is too slow...2 days only 250 s) and to fully understand all the data
that I can choose in the definition of the fire.
I created a model of this car parking with three car, the one in the
centre is a vent burning with the HRR of Schleich et al. (1999)
reference curve, but to create the fire for the 2 other cars (one on
the left side, the other one on the right side) I cannot use
Schleich's data, because our parking has a sprinkler system. So I've
thought to create the other 2 cars as a solid which surface has an
ignition temperature. What do you think about this way of thinking?
Reasonable? (obiouvsly I'll have to reflect about the ignition temp of
a car that it's not simple)
Another question is about the reaction. I chose POLYURETHANE as
reaction and I've some doubts for the values os Soot Yield, CO Yield
and H2 Yield. About the Soot Yield I read old discussions and I chose
a reasonable value of 0,1. In my simulation I chose also a value for
the CO and H2 Yield of 0,01 both...What do you think about these
values?
Best regards,
matteo
>
> - Mostra testo tra virgolette -
Hostikka Simo
Mar 3, 2008, 5:11:05 AM3/3/08
to fds...@googlegroups.com
At this point everything will become much more difficult and more uncertain.
It's not just choosing a proper ignition temperature,
but the modelling of the whole chain of
source of thermal radiation -
specification of water spray -
reproduction of water spray -
radiation attenuation by spray -
solid heating -
solid pyrolysis.
It's not just choosing a proper ignition temperature,
but the modelling of the whole chain of
source of thermal radiation -
specification of water spray -
reproduction of water spray -
radiation attenuation by spray -
solid heating -
solid pyrolysis.
All of these topics are more difficult than using prescribed fire to compute
smoke spread and heating of floor slabs or steel beams.
I would suggest you think again with your professor, do you really have the
necessary skills and data to do the analysis. Sure, you will learn a lot,
and create the skills, but still you may not know all the
facts you need in order to modell the things I mentioned above.
Simo
> So I've thought to create the other 2 cars
> as a solid which surface has an ignition temperature. What do
> you think about this way of thinking?
>
mattiperr
Mar 5, 2008, 3:46:27 AM3/5/08
to FDS and Smokeview Discussions
Thank you very much for your suggestions!
What you said is correct, we're creating our skills, also asking and
working with other professors.
Another doubt is about the smoke. I read in some past topics that in
comparison with FDS4 now it's better to define both inside and outside
of buildings. In my case (an underground car parking) is fundamental
defining how the smoke goes out from the compartment. Smoke goes out
from several holes in the wall and goes up in chimneys till the height
of the street (4,9 m height).
If my Z-domain boundary is the heigth of 4,9 m and I create an open
vent on the top of my chimney, am I sure that smoke goes out of there?
Or is it better to create a bigger domain including the outside of the
car parking?
Thnaks a lot,
matteo
> > > - Mostra testo tra virgolette -- Nascondi testo tra virgolette -
What you said is correct, we're creating our skills, also asking and
working with other professors.
Another doubt is about the smoke. I read in some past topics that in
comparison with FDS4 now it's better to define both inside and outside
of buildings. In my case (an underground car parking) is fundamental
defining how the smoke goes out from the compartment. Smoke goes out
from several holes in the wall and goes up in chimneys till the height
of the street (4,9 m height).
If my Z-domain boundary is the heigth of 4,9 m and I create an open
vent on the top of my chimney, am I sure that smoke goes out of there?
Or is it better to create a bigger domain including the outside of the
car parking?
Thnaks a lot,
matteo
mattiperr
Mar 5, 2008, 5:12:35 AM3/5/08
to FDS and Smokeview Discussions
Another quick doubt...
I read in the User's Guide (10.7) that "if the surface has been
assigned a HRRPUA a parameter needs to be specified" i.e.
E_COEFFICIENT.
If I modelled my HRRPUA with a time-dependent ramp and some spinklers,
is it necessary to choose this extinguishing coefficient or do
automatically my spinklers work?
thank you again
m.
I read in the User's Guide (10.7) that "if the surface has been
assigned a HRRPUA a parameter needs to be specified" i.e.
E_COEFFICIENT.
If I modelled my HRRPUA with a time-dependent ramp and some spinklers,
is it necessary to choose this extinguishing coefficient or do
automatically my spinklers work?
thank you again
m.
Kevin
Mar 5, 2008, 8:18:33 AM3/5/08
to FDS and Smokeview Discussions
If you have specified the heat release rate, what information would
the model have to determine the decrease in the HRR due to water? The
empirical E_COEFFICIENT is used to decrease the HRR according to
HRR = HRR_specified * exp(-E_COEFF*t)
You must decide what value of E_COEFF to use, based on experimental
data. The model cannot predict fire suppression of a burning car
unless more detail is given about its materials and geometry. Even
then, this would be extremely difficult to predict, and you are better
off using empirical data.
> > - Mostra testo tra virgolette -- Hide quoted text -
>
> - Show quoted text -
the model have to determine the decrease in the HRR due to water? The
empirical E_COEFFICIENT is used to decrease the HRR according to
HRR = HRR_specified * exp(-E_COEFF*t)
You must decide what value of E_COEFF to use, based on experimental
data. The model cannot predict fire suppression of a burning car
unless more detail is given about its materials and geometry. Even
then, this would be extremely difficult to predict, and you are better
off using empirical data.
>
> - Show quoted text -
Kevin
Mar 5, 2008, 8:48:54 AM3/5/08
to FDS and Smokeview Discussions
The pressure boundary condition at OPEN boundaries is only
approximate. I suggest that if you are interested in the flow of
anything through an opening that you extend the computational domain
beyond the opening by at least a meter.
approximate. I suggest that if you are interested in the flow of
anything through an opening that you extend the computational domain
beyond the opening by at least a meter.
mattiperr
Mar 7, 2008, 9:58:46 AM3/7/08
to FDS and Smokeview Discussions
Thank you very much, I solved all these problems.
Everything now seems to be ok and also the internal temperatures have
sense.
There's only one side of this model that's not so clear. I modelled 3
cars as 3 vents. The middle one has his own HRR-curve (I took values
form SFPE Handbook) and the question is about the other 2 car/vents.
For example, if I want that the other 2 cars will ignite at a
temperature of 300°C which is the right way of modelling?
The car/vent in the middle is a vent "BURNER" and the other 2 are
"LAYERED" with the same properties of the first one (same HRR, same
ramp) but they have an ignition temp of 300°C. Is it correct or FDS
canot recognize the ignition temp of a simple vent?
Thank you again
> > > > as a solid which surface has anignitiontemperature. What do
> > - Show quoted text -- Nascondi testo tra virgolette -
Everything now seems to be ok and also the internal temperatures have
sense.
There's only one side of this model that's not so clear. I modelled 3
cars as 3 vents. The middle one has his own HRR-curve (I took values
form SFPE Handbook) and the question is about the other 2 car/vents.
For example, if I want that the other 2 cars will ignite at a
temperature of 300°C which is the right way of modelling?
The car/vent in the middle is a vent "BURNER" and the other 2 are
"LAYERED" with the same properties of the first one (same HRR, same
ramp) but they have an ignition temp of 300°C. Is it correct or FDS
canot recognize the ignition temp of a simple vent?
Thank you again
daserra
Mar 8, 2008, 11:48:52 AM3/8/08
to FDS and Smokeview Discussions
I would model the two cars as obstacles with a surface that ignites at
300°C and play around a little with the properties of these obstacles.
I think that the plastic inside the car start to burn first and than
the heat produced by this sets everything on fire rapidly. You can
check the radiation on these obstacles. Once set on fire FDS will do
the rest.
I saw a test on TV lately where they put a pan with some kerosin under
the car and the car fire started inside the car and after 3 minutes
the car was completely on fire. German ADAC did this test to prove the
safety of LPG tanks.
You can find a very detailed test report on the Internet:
http://www.adac.de/Search/SearchResult/RW_HighLight.asp?RWDoc2Show=40259&RWLang=de&RWCollectionID=adac&RWQuery=brand&RWURL=http://www.adac.de/Tests/Crash_Tests/Gas/Heckcrash_Gastank/Brandversuch/default.asp&RWCookieValue=
300°C and play around a little with the properties of these obstacles.
I think that the plastic inside the car start to burn first and than
the heat produced by this sets everything on fire rapidly. You can
check the radiation on these obstacles. Once set on fire FDS will do
the rest.
I saw a test on TV lately where they put a pan with some kerosin under
the car and the car fire started inside the car and after 3 minutes
the car was completely on fire. German ADAC did this test to prove the
safety of LPG tanks.
You can find a very detailed test report on the Internet:
http://www.adac.de/Search/SearchResult/RW_HighLight.asp?RWDoc2Show=40259&RWLang=de&RWCollectionID=adac&RWQuery=brand&RWURL=http://www.adac.de/Tests/Crash_Tests/Gas/Heckcrash_Gastank/Brandversuch/default.asp&RWCookieValue=
daserra
Mar 8, 2008, 12:03:33 PM3/8/08
to FDS and Smokeview Discussions
Did you already try www.youtube.com for real life burning cars: just
type: car burning
On 8 Mrz., 17:48, daserra <m...@grs.de> wrote:
> I would model the two cars as obstacles with a surface that ignites at
> 300°C and play around a little with the properties of these obstacles.
> I think that the plastic inside the car start to burn first and than
> the heat produced by this sets everything on fire rapidly. You can
> check the radiation on these obstacles. Once set on fire FDS will do
> the rest.
> I saw a test on TV lately where they put a pan with some kerosin under
> the car and the car fire started inside the car and after 3 minutes
> the car was completely on fire. German ADAC did this test to prove the
> safety of LPG tanks.
>
> You can find a very detailed test report on the Internet:
>
> http://www.adac.de/Search/SearchResult/RW_HighLight.asp?RWDoc2Show=40...
type: car burning
On 8 Mrz., 17:48, daserra <m...@grs.de> wrote:
> I would model the two cars as obstacles with a surface that ignites at
> 300°C and play around a little with the properties of these obstacles.
> I think that the plastic inside the car start to burn first and than
> the heat produced by this sets everything on fire rapidly. You can
> check the radiation on these obstacles. Once set on fire FDS will do
> the rest.
> I saw a test on TV lately where they put a pan with some kerosin under
> the car and the car fire started inside the car and after 3 minutes
> the car was completely on fire. German ADAC did this test to prove the
> safety of LPG tanks.
>
> You can find a very detailed test report on the Internet:
>
daserra
Mar 8, 2008, 12:12:41 PM3/8/08
to FDS and Smokeview Discussions
"car burning on I 10" on youtube: watch the guy walking close to the
car. The radiation is not really strong but there is a lot of smoke.
On 8 Mrz., 18:03, daserra <m...@grs.de> wrote:
> Did you already trywww.youtube.comfor real life burning cars: just
car. The radiation is not really strong but there is a lot of smoke.
On 8 Mrz., 18:03, daserra <m...@grs.de> wrote:
> Did you already trywww.youtube.comfor real life burning cars: just
mattiperr
Mar 10, 2008, 5:53:19 AM3/10/08
to FDS and Smokeview Discussions
Thanks for your answer...I modelled the central car (the first one
that ignite) as OBST with 3 surfaces set as 'BURNER' (Xmin, Xmax and
Zmax). Also the other 2 cars (one on the right side, the other one on
the left side) are OBST but I want that they become to ignite once
reached the temp of 300°C. It seems that I cannot do it if I don't
give any info about the material...isn't it?
Other question...my sprinklers work but they don't seem to affect the
RAMP of HRR. In this way it seems to me that sprinklers reduce the
temperature, reduce the HRRPUA but they don't seem to fasten the
extinguishing of fire. What can I do to affect the HRR-curve? Should I
give an extinguishing coefficient?
Thankx
On 8 Mar, 18:12, daserra <m...@grs.de> wrote:
> "car burning on I 10" on youtube: watch the guy walking close to the
> car. The radiation is not really strong but there is a lot of smoke.
>
> On 8 Mrz., 18:03, daserra <m...@grs.de> wrote:
>
>
>
> > Did you already trywww.youtube.comforreal life burning cars: just
> > > > > - Mostra testo tra virgolette -- Nascondi testo tra virgolette -
that ignite) as OBST with 3 surfaces set as 'BURNER' (Xmin, Xmax and
Zmax). Also the other 2 cars (one on the right side, the other one on
the left side) are OBST but I want that they become to ignite once
reached the temp of 300°C. It seems that I cannot do it if I don't
give any info about the material...isn't it?
Other question...my sprinklers work but they don't seem to affect the
RAMP of HRR. In this way it seems to me that sprinklers reduce the
temperature, reduce the HRRPUA but they don't seem to fasten the
extinguishing of fire. What can I do to affect the HRR-curve? Should I
give an extinguishing coefficient?
Thankx
On 8 Mar, 18:12, daserra <m...@grs.de> wrote:
> "car burning on I 10" on youtube: watch the guy walking close to the
> car. The radiation is not really strong but there is a lot of smoke.
>
> On 8 Mrz., 18:03, daserra <m...@grs.de> wrote:
>
>
>
Kevin
Mar 10, 2008, 8:12:54 AM3/10/08
to FDS and Smokeview Discussions
Yes, you need to specify an E_COEFFICIENT to tell FDS at what rate to
reduce the HRR. But wait for 5.1.4, as someone else identified a bug
with this feature. The new version should be out this week.
On Mar 10, 5:53 am, mattiperr <mattip...@gmail.com> wrote:
> Thanks for your answer...I modelled the central car (the first one
> that ignite) as OBST with 3 surfaces set as 'BURNER' (Xmin, Xmax and
> Zmax). Also the other 2 cars (one on the right side, the other one on
> the left side) are OBST but I want that they become to ignite once
> reached the temp of 300°C. It seems that I cannot do it if I don't
> give any info about the material...isn't it?
>
> Other question...my sprinklers work but they don't seem to affect the
> RAMP of HRR. In this way it seems to me that sprinklers reduce the
> temperature, reduce the HRRPUA but they don't seem to fasten the
> extinguishing of fire. What can I do to affect the HRR-curve? Should I
> give an extinguishing coefficient?
>
> Thankx
>
> On 8 Mar, 18:12, daserra <m...@grs.de> wrote:
>
>
>
> > "car burning on I 10" on youtube: watch the guy walking close to the
> > car. The radiation is not really strong but there is a lot of smoke.
>
> > On 8 Mrz., 18:03, daserra <m...@grs.de> wrote:
>
> > > Did you already trywww.youtube.comforreallife burning cars: just
reduce the HRR. But wait for 5.1.4, as someone else identified a bug
with this feature. The new version should be out this week.
On Mar 10, 5:53 am, mattiperr <mattip...@gmail.com> wrote:
> Thanks for your answer...I modelled the central car (the first one
> that ignite) as OBST with 3 surfaces set as 'BURNER' (Xmin, Xmax and
> Zmax). Also the other 2 cars (one on the right side, the other one on
> the left side) are OBST but I want that they become to ignite once
> reached the temp of 300°C. It seems that I cannot do it if I don't
> give any info about the material...isn't it?
>
> Other question...my sprinklers work but they don't seem to affect the
> RAMP of HRR. In this way it seems to me that sprinklers reduce the
> temperature, reduce the HRRPUA but they don't seem to fasten the
> extinguishing of fire. What can I do to affect the HRR-curve? Should I
> give an extinguishing coefficient?
>
> Thankx
>
> On 8 Mar, 18:12, daserra <m...@grs.de> wrote:
>
>
>
> > "car burning on I 10" on youtube: watch the guy walking close to the
> > car. The radiation is not really strong but there is a lot of smoke.
>
> > On 8 Mrz., 18:03, daserra <m...@grs.de> wrote:
>
mattiperr
Mar 21, 2008, 3:48:45 AM3/21/08
to FDS and Smokeview Discussions
Today's my last day working on FDS...In two months I really improved
my competences, also if there's a lot of work to do!
I just want to thank you all the people here...Kevin, Timo,
daserra...all the people that answered me also at the beginning when
my questions were a little bit stupid for an advanced user!
Good job and happy Easter...
matteo
On 10 Mar, 13:12, Kevin <mcgra...@gmail.com> wrote:
> Yes, you need to specify an E_COEFFICIENT to tell FDS at what rate to
> reduce the HRR. But wait for 5.1.4, as someone else identified a bug
> with this feature. The new version should be out this week.
>
> On Mar 10, 5:53 am, mattiperr <mattip...@gmail.com> wrote:
>
>
>
> > Thanks for your answer...I modelled the central car (the first one
> > that ignite) as OBST with 3 surfaces set as 'BURNER' (Xmin, Xmax and
> > Zmax). Also the other 2 cars (one on the right side, the other one on
> > the left side) are OBST but I want that they become to ignite once
> > reached the temp of 300°C. It seems that I cannot do it if I don't
> > give any info about the material...isn't it?
>
> > Other question...my sprinklers work but they don't seem to affect the
> > RAMP of HRR. In this way it seems to me that sprinklers reduce the
> > temperature, reduce the HRRPUA but they don't seem to fasten the
> > extinguishing of fire. What can I do to affect the HRR-curve? Should I
> > give an extinguishing coefficient?
>
> > Thankx
>
> > On 8 Mar, 18:12, daserra <m...@grs.de> wrote:
>
> > > "car burning on I 10" on youtube: watch the guy walking close to the
> > > car. The radiation is not really strong but there is a lot of smoke.
>
> > > On 8 Mrz., 18:03, daserra <m...@grs.de> wrote:
>
> > > > Did you already trywww.youtube.comforreallifeburning cars: just
> > - Show quoted text -- Nascondi testo tra virgolette -
my competences, also if there's a lot of work to do!
I just want to thank you all the people here...Kevin, Timo,
daserra...all the people that answered me also at the beginning when
my questions were a little bit stupid for an advanced user!
Good job and happy Easter...
matteo
On 10 Mar, 13:12, Kevin <mcgra...@gmail.com> wrote:
> Yes, you need to specify an E_COEFFICIENT to tell FDS at what rate to
> reduce the HRR. But wait for 5.1.4, as someone else identified a bug
> with this feature. The new version should be out this week.
>
> On Mar 10, 5:53 am, mattiperr <mattip...@gmail.com> wrote:
>
>
>
> > Thanks for your answer...I modelled the central car (the first one
> > that ignite) as OBST with 3 surfaces set as 'BURNER' (Xmin, Xmax and
> > Zmax). Also the other 2 cars (one on the right side, the other one on
> > the left side) are OBST but I want that they become to ignite once
> > reached the temp of 300°C. It seems that I cannot do it if I don't
> > give any info about the material...isn't it?
>
> > Other question...my sprinklers work but they don't seem to affect the
> > RAMP of HRR. In this way it seems to me that sprinklers reduce the
> > temperature, reduce the HRRPUA but they don't seem to fasten the
> > extinguishing of fire. What can I do to affect the HRR-curve? Should I
> > give an extinguishing coefficient?
>
> > Thankx
>
> > On 8 Mar, 18:12, daserra <m...@grs.de> wrote:
>
> > > "car burning on I 10" on youtube: watch the guy walking close to the
> > > car. The radiation is not really strong but there is a lot of smoke.
>
> > > On 8 Mrz., 18:03, daserra <m...@grs.de> wrote:
>
maciek
Apr 4, 2008, 9:46:19 AM4/4/08
to FDS and Smokeview Discussions
Hello
I have a similar computations to do. Fire of two cars in the steel-
frame car parking with a concrete slabs. but what interested me the
most, is the thermal response of the steel. I want to model this in
Ansys. but first I need to have an appropriate thermal boundary
conditions. so I modelled it in FDS and I wanted to take the
WALL_TEMPERATURE of steel beams and transfer it into Ansys as an area
temperature. But, I noticed that the temperature of steel beams is
much lower then of concrete slabs. So I make a very simple example,
which is below, and when I replece SURF_DEFAULT='concrete_surf' with
'steel_surf' it seems that steel heats much slower then concrete. can
You see any mistake in this input file? I tried also different
geometry so I think it's not the case. I also think of transferring to
ansys 'HEAT_FLUX' but it also seems not to work properly. or maybe
everything is ok, and steel is really heatting up slower then
concrete? But it doesn't sound good to me. I can't go any further
without this, so please help :)
Maciek
&HEAD CHID='example', TITLE='burn' /
units:
dimesnion=m
specific_heat= kJ/kg*C
conductivity=W/m*K
density=kg/m^3
temperature=C
&MESH IJK=20,20,20, XB=-2, 2,-2.0, 2.0, -0, 2.5 /
&TIME TWFIN=30 /
&MISC SURF_DEFAULT='concrete_surf' /
&MATL ID = 'CONCRETE'
SPECIFIC_HEAT = 0.88
CONDUCTIVITY = 1.2
DENSITY = 2200./
&MATL ID = 'STEEL'
SPECIFIC_HEAT = 0.45
CONDUCTIVITY = 48
DENSITY = 7850./
&SURF ID = 'concrete_surf'
RGB = 200,200,200
MATL_ID = 'CONCRETE'
thickness = 0.2/
&SURF ID = 'steel_surf'
RGB = 100,200,200
MATL_ID = 'STEEL'
thickness = 0.2/
&SURF ID='BURNER', COLOR='YELLOW', HRRPUA=1500, /
&OBST XB=-1.7 , 1.7 ,-1.7 , 1.7 , 2 ,3, / ceiling
&VENT XB=-2, 2,-2 , 2, 0, 0, SURF_ID='BURNER' /
&VENT MB='XMIN', SURF_ID='OPEN' /
&VENT MB='XMAX', SURF_ID='OPEN' /
&VENT MB='YMIN', SURF_ID='OPEN' /
&VENT MB='YMAX', SURF_ID='OPEN' /
&BNDF QUANTITY='WALL_TEMPERATURE' /
&BNDF QUANTITY='HEAT_FLUX' /
&TAIL /
> > > > > Did you already trywww.youtube.comforreallifeburningcars: just
I have a similar computations to do. Fire of two cars in the steel-
frame car parking with a concrete slabs. but what interested me the
most, is the thermal response of the steel. I want to model this in
Ansys. but first I need to have an appropriate thermal boundary
conditions. so I modelled it in FDS and I wanted to take the
WALL_TEMPERATURE of steel beams and transfer it into Ansys as an area
temperature. But, I noticed that the temperature of steel beams is
much lower then of concrete slabs. So I make a very simple example,
which is below, and when I replece SURF_DEFAULT='concrete_surf' with
'steel_surf' it seems that steel heats much slower then concrete. can
You see any mistake in this input file? I tried also different
geometry so I think it's not the case. I also think of transferring to
ansys 'HEAT_FLUX' but it also seems not to work properly. or maybe
everything is ok, and steel is really heatting up slower then
concrete? But it doesn't sound good to me. I can't go any further
without this, so please help :)
Maciek
&HEAD CHID='example', TITLE='burn' /
units:
dimesnion=m
specific_heat= kJ/kg*C
conductivity=W/m*K
density=kg/m^3
temperature=C
&MESH IJK=20,20,20, XB=-2, 2,-2.0, 2.0, -0, 2.5 /
&TIME TWFIN=30 /
&MISC SURF_DEFAULT='concrete_surf' /
&MATL ID = 'CONCRETE'
SPECIFIC_HEAT = 0.88
CONDUCTIVITY = 1.2
DENSITY = 2200./
&MATL ID = 'STEEL'
SPECIFIC_HEAT = 0.45
CONDUCTIVITY = 48
DENSITY = 7850./
&SURF ID = 'concrete_surf'
RGB = 200,200,200
MATL_ID = 'CONCRETE'
thickness = 0.2/
&SURF ID = 'steel_surf'
RGB = 100,200,200
MATL_ID = 'STEEL'
thickness = 0.2/
&SURF ID='BURNER', COLOR='YELLOW', HRRPUA=1500, /
&OBST XB=-1.7 , 1.7 ,-1.7 , 1.7 , 2 ,3, / ceiling
&VENT XB=-2, 2,-2 , 2, 0, 0, SURF_ID='BURNER' /
&VENT MB='XMIN', SURF_ID='OPEN' /
&VENT MB='XMAX', SURF_ID='OPEN' /
&VENT MB='YMIN', SURF_ID='OPEN' /
&VENT MB='YMAX', SURF_ID='OPEN' /
&BNDF QUANTITY='WALL_TEMPERATURE' /
&BNDF QUANTITY='HEAT_FLUX' /
&TAIL /
Kevin
Apr 4, 2008, 9:52:31 AM4/4/08
to FDS and Smokeview Discussions
Steel conducts heat better than concrete. Thus, concrete heats up at
the surface more quickly than steel because steel conducts the heat
more rapidly to the interior.
If you want to transfer information to ANSYS, read the FDS User's
Guide section on ADIABATIC_SURFACE_TEMPERATURE, and read Wickstrom's
paper in last year's Interflam proceedings.
> > > > > > > > > > > > I put the- Hide quoted text -
>
> - Show quoted text -...
>
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the surface more quickly than steel because steel conducts the heat
more rapidly to the interior.
If you want to transfer information to ANSYS, read the FDS User's
Guide section on ADIABATIC_SURFACE_TEMPERATURE, and read Wickstrom's
paper in last year's Interflam proceedings.
>
> - Show quoted text -...
>
> read more »
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