[yingkun]

Hi,Thomas
I chang the species temperature rangs in therm.dat file,it works,the only thing is that I need to know whether the result is correct,I'm going to check it...

[bfisch90]

Hallo Yingkun,

maybe you could try to find out, if the nasa database has new thermodynamic data for your species, which are valid for temperatures up to 6000 K.
http://www.grc.nasa.gov/WWW/CEAWeb/ceaThermoBuild.htm

Good luck
Thomas

[yingkun]

it's good for me,thanks!

[Rophys]

Hello all,

I tried to use the NASA web site but I didn't understand so much the output.
For example, I choose the element N (atomic nitrogen) and after this I choose N2 (molecular nitrogen). Next step, I choose the temperature range from 273 to 500 K, and I get the following output :

N2

OPTIONS: joules

TEMPERATURE SCHEDULE

273.000 283.000 293.000 298.150 303.000 313.000
323.000 333.000 343.000 353.000 363.000 373.000
383.000 393.000 400.000

NOTE: Thermodynamic properties calculated for temperatures outside the range of
the fitted data may have large errors. This program allows calculations only
for temperatures within 20% above or below the fitted temperature range.


COEFFICIENTS FOR FITTED THERMODYNAMIC FUNCTIONS


N2 Ref-Elm. Gurvich,1978 pt1 p280 pt2 p207.
3 tpis78 N 2.00 0.00 0.00 0.00 0.00 0 28.01340 0.000
200.000 1000.000 7 -2.0 -1.0 0.0 1.0 2.0 3.0 4.0 0.0 8670.104
2.210371497E+04-3.818461820E+02 6.082738360E+00-8.530914410E-03 1.384646189E-05
-9.625793620E-09 2.519705809E-12 0.000000000E+00 7.108460860E+02-1.076003744E+01
1000.000 6000.000 7 -2.0 -1.0 0.0 1.0 2.0 3.0 4.0 0.0 8670.104
5.877124060E+05-2.239249073E+03 6.066949220E+00-6.139685500E-04 1.491806679E-07
-1.923105485E-11 1.061954386E-15 0.000000000E+00 1.283210415E+04-1.586640027E+01
6000.000 20000.000 7 -2.0 -1.0 0.0 1.0 2.0 3.0 4.0 0.0 8670.104
8.310139160E+08-6.420733540E+05 2.020264635E+02-3.065092046E-02 2.486903333E-06
-9.705954110E-11 1.437538881E-15 0.000000000E+00 4.938707040E+06-1.672099740E+03

.
.
.

According to the User Guide (U-177) Cp is calculated as follow:
Cp=R((((a1T+a3)T+a2)T+a1)T+a0)
and we need 2 constants of integration a5 and a6.

My question is, which of this parameters corresponds to a0, a1, a2, a3, a4, a5 and a6 ? If this website is not properly to obtain this value, there is another reference ?
My apologise for this question, it is a bit long

[bfisch90]

Hallo,

the output of the NASA-database is based on the newer Janaf model with 9 coefficients (a1-a7, b1, b2).

a1 a2 a3 a4
2.210371497E+04-3.818461820E+02 6.082738360E+00-8.530914410E-03
a5
1.384646189E-05
a6 a7 placeholder
-9.625793620E-09 2.519705809E-12 0.000000000E+00
b1 b2
7.108460860E+02-1.076003744E+01


Equations newer Janaf model
Cp(T) = R( a[1]/T^2 + a[2]/T+ a[3] + a[4]T + a[5]T^2 + a[6]T^3 + a[7]T^4 )
H(T) = R( -a[1]/T + a[2]lnT + a[3]T + (a[4]T^2)/2 + (a[5]T^3)/3 + (a[6]T^4)/4 + (a[7]T^5)/5 + b[1] )
S(T) = R( -a[1]/(2*T^2) - a[2]/T + a[3] lnT + a[4]T + (a[5]T^2)/2 + (a[6]T^3)/3 + (a[7]T^4)/4 + b[2] )

The official version of OpenFOAM has implemented only the old Janaf model.

So you have different choices e.g.:
- Convert the thermodata (from the NASA database) into the old format
- Implement the newer Janaf model to OpenFOAM
http://openfoamwiki.net/index.php/Janaf4
- use a thermodata file which is already in the old format and contains the species you need.
ftp://ftp.technion.ac.il/pub/support...mics/THERM.DAT

Thomas

Originally Posted by Rophys

Hello all,

I tried to use the NASA web site but I didn't understand so much the output.
For example, I choose the element N (atomic nitrogen) and after this I choose N2 (molecular nitrogen). Next step, I choose the temperature range from 273 to 500 K, and I get the following output :

N2

OPTIONS: joules

TEMPERATURE SCHEDULE

273.000 283.000 293.000 298.150 303.000 313.000
323.000 333.000 343.000 353.000 363.000 373.000
383.000 393.000 400.000

NOTE: Thermodynamic properties calculated for temperatures outside the range of
the fitted data may have large errors. This program allows calculations only
for temperatures within 20% above or below the fitted temperature range.


COEFFICIENTS FOR FITTED THERMODYNAMIC FUNCTIONS


N2 Ref-Elm. Gurvich,1978 pt1 p280 pt2 p207.
3 tpis78 N 2.00 0.00 0.00 0.00 0.00 0 28.01340 0.000
200.000 1000.000 7 -2.0 -1.0 0.0 1.0 2.0 3.0 4.0 0.0 8670.104
2.210371497E+04-3.818461820E+02 6.082738360E+00-8.530914410E-03 1.384646189E-05
-9.625793620E-09 2.519705809E-12 0.000000000E+00 7.108460860E+02-1.076003744E+01
1000.000 6000.000 7 -2.0 -1.0 0.0 1.0 2.0 3.0 4.0 0.0 8670.104
5.877124060E+05-2.239249073E+03 6.066949220E+00-6.139685500E-04 1.491806679E-07
-1.923105485E-11 1.061954386E-15 0.000000000E+00 1.283210415E+04-1.586640027E+01
6000.000 20000.000 7 -2.0 -1.0 0.0 1.0 2.0 3.0 4.0 0.0 8670.104
8.310139160E+08-6.420733540E+05 2.020264635E+02-3.065092046E-02 2.486903333E-06
-9.705954110E-11 1.437538881E-15 0.000000000E+00 4.938707040E+06-1.672099740E+03

.
.
.

According to the User Guide (U-177) Cp is calculated as follow:
Cp=R((((a1T+a3)T+a2)T+a1)T+a0)
and we need 2 constants of integration a5 and a6.

My question is, which of this parameters corresponds to a0, a1, a2, a3, a4, a5 and a6 ? If this website is not properly to obtain this value, there is another reference ?
My apologise for this question, it is a bit long

[Rophys]

Hi Thomas,

Thanks for this. Again I have two more questions.

1) The file therm.dat only give me information about a0....a4. How can I calculate the a5 and a6 (constants of integration). ?

2) Taking in to account the air data, which line corresponds to high and low temperature coefficients ? And the common temperature ?

AIR L 9/95 WARNING! 0G 200.000 6000.000 1000. 1
3.08792717E+00 1.24597184E-03-4.23718945E-07 6.74774789E-1-3.97076972E-15 2
-9.95262755E+02 5.95960930E+00 3.56839620E+00-6.78729429E-04 55371476E-06 3
-3.29937060E-12-4.66395387E-13-1.06234659E+03 71582965E+00-1.50965000E+01 4

line 1
200.000 - lower temperature limit
6000.000 - upper temperature limit
1000 - common temperature

line 2
corresponds to low cp coeff ?

line 3
corresponds to high cp coeff ?

line 4
corresponds to common temperature cp coeff ?

Is it correct ?

Thanks very much

[bfisch90]

Hallo,

In the old janaf tables, you have only two temperature ranges (low and high). The first 7 parameters belong to the high temperature range. a5 and a6 are the constants of integration.
(You could test this by just plotting cp, h and s.)
The janaf table with 15 coefficients is an updated version:
The 7 term polynomials actually include 15 constants. The first set of 7 constants belongs to the 1000-6000 K polynomial, the second set of 7 constants belongs to the 200-1000 K polynomial, and the fifteenth constant is H298/R ≡ ΔfH298/R.

Thomas

high temperature range (1000K-6000K)
a0 a1 a2 a3 a4
3.08792717E+00 1.24597184E-03-4.23718945E-07 6.74774789E-1-3.97076972E-15 2
a5 a6 low temperature range (200K-1000K) a0 a1 a2
-9.95262755E+02 5.95960930E+00 3.56839620E+00-6.78729429E-04 55371476E-06 3
a3 a4 a5 a6 H298/R
-3.29937060E-12-4.66395387E-13-1.06234659E+03 71582965E+00-1.50965000E+01 4

Cp(T) = R( a[0] + a[1]T + a[2]T^2 + a[3]T^3 + a[4]T^4 )
H(T) = R( a[0]T + (a[1]T^2)/2 + (a[2]T^3)/3 + (a[3]T^4)/4 + (a[4]T^5)/5 + a[5] )
S(T) = R( a[0] lnT + a[1]T + (a[2]T^2)/2 + (a[3]T^3)/3 + (a[4]T^4)/4 + a[6] )

Originally Posted by Rophys

Hi Thomas,

Thanks for this. Again I have two more questions.

1) The file therm.dat only give me information about a0....a4. How can I calculate the a5 and a6 (constants of integration). ?

2) Taking in to account the air data, which line corresponds to high and low temperature coefficients ? And the common temperature ?

AIR L 9/95 WARNING! 0G 200.000 6000.000 1000. 1
3.08792717E+00 1.24597184E-03-4.23718945E-07 6.74774789E-1-3.97076972E-15 2
-9.95262755E+02 5.95960930E+00 3.56839620E+00-6.78729429E-04 55371476E-06 3
-3.29937060E-12-4.66395387E-13-1.06234659E+03 71582965E+00-1.50965000E+01 4

line 1
200.000 - lower temperature limit
6000.000 - upper temperature limit
1000 - common temperature

line 2
corresponds to low cp coeff ?

line 3
corresponds to high cp coeff ?

line 4
corresponds to common temperature cp coeff ?

Is it correct ?

Thanks very much

[Rophys]

Hi Thomas,

Thanks for this.

Now is very clear to me the janaf table.

[MPJ]

hello everyone,
it seems that the download link for the new janaf table in the openfoamwikiis not avaible now.
The URL of openfoamwiki is:
http://openfoamwiki.net/index.php/Janaf
can somebody send me a copy of these file?
my email address is oliver.pasqual@gmail.com
Thanks
oliver P

[Rophys]

MPJ,

The new JANAF table is not implemented in the OpenFoam. In your simulation you need to use the values from the old table. The link that you sent in your post there contains both tables (old and new JANAF).

old JANAF: ftp://ftp.technion.ac.il/pub/support...mics/THERM.DAT

new JANAF: http://www.galcit.caltech.edu/EDL/pu...rmo/thermo.inp

Regards,

Rodrigo

[MPJ]

Originally Posted by Rophys

MPJ,

The new JANAF table is not implemented in the OpenFoam. In your simulation you need to use the values from the old table. The link that you sent in your post there contains both tables (old and new JANAF).

old JANAF: ftp://ftp.technion.ac.il/pub/support...mics/THERM.DAT

new JANAF: http://www.galcit.caltech.edu/EDL/pu...rmo/thermo.inp

Regards,

Rodrigo

Hi Rodrigo,
thanks for your kindly reply.
sorry for the undetailed description.
The janaf table can be obtained, but the URL for new janaf model is not avaible.
it's the message from the developer that the link will be updated soon(Thx, Thomas)

Have a nice day
Oliver

[MPJ]

hello everyone,
The downloading URL for new janaf model in the wiki is not avaiable for a long time.
I want to obtain these files, so it will be highly appreciated if someone send me a copy of these file or tell me where I can get them.
oliver

[Rophys]

Dear Oliver,

Just download the new Janaf using the following link:

new JANAF: http://www.galcit.caltech.edu/EDL/pu...rmo/thermo.inp

open the website, copy all the data (ctrl+a) and paste it in .txt file (you can create a .txt using a text editor like notepad).

Cheers.

[MPJ]

Originally Posted by Rophys

Dear Oliver,

Just download the new Janaf using the following link:

new JANAF: http://www.galcit.caltech.edu/EDL/pu...rmo/thermo.inp

open the website, copy all the data (ctrl+a) and paste it in .txt file (you can create a .txt using a text editor like notepad).

Cheers.

Dear Rophys,
Thanks for you kindly reply and your patient help.
yes the janaf table can be obtained from URL your given.
From the openfoamwiki
( http://openfoamwiki.net/index.php/Janaf ),
we got:
The old janaf tables uses 7 coefficients and 2 polynomials for a lower and a higher temperature range,and the old janaf tables are valid for temperatures up to 6000 K.
The newer janaf model can be used to handle a larger temperature range up to 30000 K.
But the temperature dependent values of Cp, H and S are calculated with 3 polynomials using 9 coefficients.
so only obtain the new janaf tables has none effect on solving the problem. firstly we should replace the older janaf model source code files, and then compile to refresh the library.
but the source code URL describeds in the install section of wiki is not avaible for a long time.
that is :
------------------------------------------------------
2.2.1 How to install

1.Download and unzip the following folders:
http://www.daten.media-agentur-hof.d...land150411.zip
http://www.daten.media-agentur-hof.d...lich/janaf.zip
http://www.daten.media-agentur-hof.d...ader160411.zip
------------------------------------------------------

also the test case can't be download now.

so if you have the source code file and the test case files, could you send me a copy of them.
My email address is: oliver.pasqual@gmail.com
Great thanks!
oliver

[Alish1984]

Originally Posted by MPJ

Dear Rophys,
Thanks for you kindly reply and your patient help.
yes the janaf table can be obtained from URL your given.
From the openfoamwiki
( http://openfoamwiki.net/index.php/Janaf ),
we got:
The old janaf tables uses 7 coefficients and 2 polynomials for a lower and a higher temperature range,and the old janaf tables are valid for temperatures up to 6000 K.
The newer janaf model can be used to handle a larger temperature range up to 30000 K.
But the temperature dependent values of Cp, H and S are calculated with 3 polynomials using 9 coefficients.
so only obtain the new janaf tables has none effect on solving the problem. firstly we should replace the older janaf model source code files, and then compile to refresh the library.
but the source code URL describeds in the install section of wiki is not avaible for a long time.
that is :
------------------------------------------------------
2.2.1 How to install

1.Download and unzip the following folders:
http://www.daten.media-agentur-hof.d...land150411.zip
http://www.daten.media-agentur-hof.d...lich/janaf.zip
http://www.daten.media-agentur-hof.d...ader160411.zip
------------------------------------------------------

also the test case can't be download now.

so if you have the source code file and the test case files, could you send me a copy of them.
My email address is: oliver.pasqual@gmail.com
Great thanks!
oliver

I have the same problem. the link to .zip source files is down. any one can help???

[Punit Walia]

Hello,
I am working on a temperature range of 1000-15000K. So i need to use newer janaf tables which have temperature range till 20000K. I have worked using the old janaf tables.. but near 4000 initial temperature, it goes out of range. Please help me to implement the new janaf model with 9 coefficients. I am using openFOAM version 2.2.0.
Thank you,

Punit Walia

[Punit Walia]

Hi Arvind,
I have to use Newer Janaf model in OpenFOAM-2.2.0. Please can you send me the source code files and the procedure to follow to implement it in 2.2.0 version of openfoam.
My email id is punit.iitb@gmail.com

Thank You

Regards,
Punit Walia

[dancfd]

Hello all,

Thank you for the data reference. Can anyone identify a technical document reference for the JANAF data for air? I cannot seem to find it and I am uncomfortable citing a website in my paper.

Thanks in advance,

Daniel

[ziemowitzima]

It seems that this question was not answered (but asked several times in the upper discussion).

Is anyone of you aware how the constants of integration are calculated ?

I know that:





but what is the value of C1 and C2, which is needed for JANAF as a6 and a7 ?

thanks
ZMM

[Momo1805]

Hello Foamers,

I am dealing with a similiar Problem concerning janafThermo out of Temp.-Range. I am injecting Propan at 1bar with T=300K with the sprayFoam solver. Mesh and boundaries are all the same as the tutorial. The first few timesteps run without problems but than my min temperature decreases within 2-3 timesteps resulting in values way underneath of 200K so my janafmodel explodes. Also I am using a boiling evaporation model as propan boils at around 240K.

Has anyone experienced the same or has any idea what I could change? Would be grateful for any help since I have no idea left. I enclose my log.file of the calculation.

Cheers Moritz