
[Sponsors] 
June 24, 2011, 21:03 

#21 
Member
桂莹
Join Date: Apr 2011
Posts: 36
Rep Power: 8 
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... 

June 26, 2011, 01:05 

#22 
New Member
T. Hoffmann
Join Date: Mar 2011
Posts: 6
Rep Power: 8 
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 

June 26, 2011, 07:27 

#23 
Member
桂莹
Join Date: Apr 2011
Posts: 36
Rep Power: 8 
it's good for me,thanks!


September 30, 2011, 18:49 

#24 
Member
R. P.
Join Date: Jul 2010
Posts: 72
Rep Power: 9 
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 RefElm. 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+043.818461820E+02 6.082738360E+008.530914410E03 1.384646189E05 9.625793620E09 2.519705809E12 0.000000000E+00 7.108460860E+021.076003744E+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+052.239249073E+03 6.066949220E+006.139685500E04 1.491806679E07 1.923105485E11 1.061954386E15 0.000000000E+00 1.283210415E+041.586640027E+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+086.420733540E+05 2.020264635E+023.065092046E02 2.486903333E06 9.705954110E11 1.437538881E15 0.000000000E+00 4.938707040E+061.672099740E+03 . . . According to the User Guide (U177) 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 

October 6, 2011, 03:39 

#25  
New Member
T. Hoffmann
Join Date: Mar 2011
Posts: 6
Rep Power: 8 
Hallo,
the output of the NASAdatabase is based on the newer Janaf model with 9 coefficients (a1a7, b1, b2). a1 a2 a3 a4 2.210371497E+043.818461820E+02 6.082738360E+008.530914410E03 a5 1.384646189E05 a6 a7 placeholder 9.625793620E09 2.519705809E12 0.000000000E+00 b1 b2 7.108460860E+021.076003744E+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 Quote:


October 6, 2011, 06:23 

#26 
Member
R. P.
Join Date: Jul 2010
Posts: 72
Rep Power: 9 
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 1.24597184E034.23718945E07 6.74774789E13.97076972E15 2 9.95262755E+02 5.95960930E+00 3.56839620E+006.78729429E04 55371476E06 3 3.29937060E124.66395387E131.06234659E+03 71582965E+001.50965000E+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 

October 6, 2011, 06:45 

#27  
New Member
T. Hoffmann
Join Date: Mar 2011
Posts: 6
Rep Power: 8 
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 10006000 K polynomial, the second set of 7 constants belongs to the 2001000 K polynomial, and the fifteenth constant is H298/R ≡ ΔfH298/R. Thomas high temperature range (1000K6000K) a0 a1 a2 a3 a4 3.08792717E+00 1.24597184E034.23718945E07 6.74774789E13.97076972E15 2 a5 a6 low temperature range (200K1000K) a0 a1 a2 9.95262755E+02 5.95960930E+00 3.56839620E+006.78729429E04 55371476E06 3 a3 a4 a5 a6 H298/R 3.29937060E124.66395387E131.06234659E+03 71582965E+001.50965000E+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] ) Quote:
Last edited by bfisch90; October 6, 2011 at 08:51. 

October 6, 2011, 07:09 

#28 
Member
R. P.
Join Date: Jul 2010
Posts: 72
Rep Power: 9 
Hi Thomas,
Thanks for this. Now is very clear to me the janaf table. 

December 6, 2011, 09:08 
download link is not avaible

#29 
New Member
Oliver Pasqual
Join Date: May 2011
Posts: 12
Rep Power: 8 
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 Last edited by MPJ; December 6, 2011 at 23:24. 

December 6, 2011, 10:08 

#30 
Member
R. P.
Join Date: Jul 2010
Posts: 72
Rep Power: 9 
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 

December 7, 2011, 10:06 

#31  
New Member
Oliver Pasqual
Join Date: May 2011
Posts: 12
Rep Power: 8 
Quote:
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 

May 2, 2012, 09:33 

#32 
New Member
Oliver Pasqual
Join Date: May 2011
Posts: 12
Rep Power: 8 
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 

May 2, 2012, 18:45 

#33 
Member
R. P.
Join Date: Jul 2010
Posts: 72
Rep Power: 9 
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. 

May 7, 2012, 09:33 

#34  
New Member
Oliver Pasqual
Join Date: May 2011
Posts: 12
Rep Power: 8 
Quote:
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.mediaagenturhof.d...land150411.zip http://www.daten.mediaagenturhof.d...lich/janaf.zip http://www.daten.mediaagenturhof.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 

July 13, 2012, 08:52 

#35  
Member
Ali Shamooni
Join Date: Oct 2010
Posts: 42
Rep Power: 9 
Quote:
I have the same problem. the link to .zip source files is down. any one can help??? 

October 23, 2013, 07:22 
Using Newer Janaf Model in OpenFOAM 2.2.0

#36 
New Member
Punit Walia
Join Date: Jul 2013
Location: Mumbai, India
Posts: 5
Rep Power: 6 
Hello,
I am working on a temperature range of 100015000K. 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 

October 24, 2013, 07:12 

#37 
New Member
Punit Walia
Join Date: Jul 2013
Location: Mumbai, India
Posts: 5
Rep Power: 6 
Hi Arvind,
I have to use Newer Janaf model in OpenFOAM2.2.0. 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 

May 5, 2014, 22:13 

#38 
Senior Member
Daniel
Join Date: Jul 2009
Location: Montreal, Canada
Posts: 156
Rep Power: 10 
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 

May 14, 2015, 07:13 
how to caclculate/find the integration constants ?

#39 
Senior Member
Mieszko Młody
Join Date: Mar 2009
Location: POLAND, USA
Posts: 142
Rep Power: 10 

February 4, 2016, 12:25 
janaf explotes sprayfoam

#40 
New Member
Moritz
Join Date: Nov 2015
Posts: 16
Rep Power: 3 
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 23 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 

Tags 
development, janaf, openfoam1.5, thermophysicalproperties 
Thread Tools  
Display Modes  


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Centrifugal Pump and Turbulence Model  Michiel  CFX  12  January 25, 2010 04:20 
Problems bout CFD model of biomass gasification, Downdraft gasifier  wanglong  FLUENT  2  November 26, 2009 00:27 
Reynolds Stress model in CFX vs Fluent  Tim  CFX  1  October 7, 2009 06:19 
help for different between les model (subgridscale model)  liuyuxuan  FLUENT  1  October 2, 2009 15:25 
Grid resolution for fullscale and down scaled model  gravis  Main CFD Forum  0  October 2, 2009 10:27 