
[Sponsors] 
March 4, 2014, 12:36 

#341 
Senior Member
Tobias Holzmann
Join Date: Oct 2010
Location: Leoben (Austria)
Posts: 1,501
Blog Entries: 6
Rep Power: 25 
No that will not help you
__________________
Best regards, Tobias Holzmann Some interesting OpenFOAM tutorials and videos on www.Holzmanncfd.de 

March 5, 2014, 01:33 

#342 
Member
vishal
Join Date: Mar 2013
Posts: 56
Rep Power: 5 
Hi Tobi,
I also simulte this swilr flame using kOmegaSST model and I plot the residual as follows.. https://www.dropbox.com/s/sqf5vuq4gg...idual_plot.pdf Why there is lots of fluctuation in P equation..? Can make some comment on this p equation?? Regards, Vishal 

March 5, 2014, 05:44 

#343 
Senior Member
Tobias Holzmann
Join Date: Oct 2010
Location: Leoben (Austria)
Posts: 1,501
Blog Entries: 6
Rep Power: 25 
Hey vishal,
hmmm ... how do you plot this graphics? Normally the residuals are from 1 to 1e6 or sth. like that. Strange residuals! For the pressure equations ... I have to make a Research for that 

March 5, 2014, 06:25 

#344 
Member
vishal
Join Date: Mar 2013
Posts: 56
Rep Power: 5 
Hi Tobi,
Actually I plot it in excel.. not accustomed in gnu plot.... Another thing regarding H calculation...for different fuel...I have no idea regarding this calculation of H?? Regards, Vishal 

March 5, 2014, 07:26 

#345  
Senior Member
Tobias Holzmann
Join Date: Oct 2010
Location: Leoben (Austria)
Posts: 1,501
Blog Entries: 6
Rep Power: 25 
Quote:
Hi, you can use pyFoam for plotting residuals (search in the Forum or openfoamwiki). For the equation of H. This is an ordinary conserved Transport equation if the Radiation model is off. Elsewise it is an ordinary tranpsort equation like Z with an additional source term (Radiation). If the Radiation is off, the Quality results of mixture fraction and "enthalpy" is similar/equal. Only the values are different. Therefor you can Derivate that this is only a Transport equation which gives the "mixture" of the adiabatic enthalpy of oxidizer and fuel. Using this mixtured "enthalpy" you can calculate the deflection to the adiabatic enthalpy of the flame if Radiation is on. a) if you have no Radiation activated this should be Zero. Due to numerical Errors you will get a very very small deflection but it can be neglected. Strange results can be calculated with wrong schemes too! b) if you have Radiation on, then you can calculate the deflection to the adiabatic flame and that is called enthalpy defect. With this value you interpolate between different PDF´s and therefor it is possible to calculate nonadiabatic flames. Now you see, that this is not a normal enthalpy equation like you have in other solvers. Hope my formulation is clear and you understand how this works (: Regards Tobi 

March 7, 2014, 06:02 

#346 
Member
Join Date: May 2013
Location: Netherlands
Posts: 30
Rep Power: 5 
Hi Vishal,
I see that you are using GriMech 3.0, can you (or anybody else) share the required "idealgas" and "reactions" files needed for flamelet generation, since I only have them for the Polimi reaction mechanisms. I know that it is also possible to build them yourself, however, I am not that experienced with Cantera at the moment. Tobi, has Alberto mentioned any time frame in which the new libOpenSmoke tool will be released (e.g. within one month or one year). Regards, 

March 7, 2014, 06:12 

#347 
Senior Member


March 7, 2014, 06:16 

#348  
Member
Join Date: May 2013
Location: Netherlands
Posts: 30
Rep Power: 5 
Quote:


March 7, 2014, 06:19 

#349 
Senior Member

They are both available in Chemkin format if I am not mistaken?


March 7, 2014, 06:21 

#350 
Member
Join Date: May 2013
Location: Netherlands
Posts: 30
Rep Power: 5 
Ok, so which file should I use then as idealgas and which as reactions in de libOpenSmoke utility?
The files of for example PolimiC1C3 are in binary format, so unfortunately cannot open them to compare this file format with GRI. 

March 7, 2014, 06:37 

#351 
Senior Member

Not sure about the files you are talking about, but I have available:
in libOpenSMOKE/utilities/kinetics/CHEMKIN: PolimiC1C3HT_1006/PolimiC1C3HT_1006.kin PolimiC1C3HT_1006/termo_1006.tdc PolimiC1C3HT_1006/tran_1006.tra and they have similar contents/format as grimech30.dat thermo30.dat transport.dat which I found from the abovementioned website. None of them are binary. I used those to generate the flamelets with the utilities that were provided by the libOpenSMOKE team. There may have been one or two corrections/replacements I had to make, but I do not remember exactly what I did almost 2 years ago. Regards, Tom 

March 7, 2014, 06:39 

#352  
Senior Member
Tobias Holzmann
Join Date: Oct 2010
Location: Leoben (Austria)
Posts: 1,501
Blog Entries: 6
Rep Power: 25 
Quote:
They are available at the crack homepage or in the first reconstructed Lib open smoke Toolbox that was made by Bruno  I mean the rebuilt of the toolbox.. the team does not mention a time when the new updates will be available for other users that's the problem because 2 years ago they mentioned that the lip open smoke tool will be upated soon but there was never a release and so its still nothing happens. Regards. Ps: I am analyzing the flamelet generator of libopensmoke
__________________
Best regards, Tobias Holzmann Some interesting OpenFOAM tutorials and videos on www.Holzmanncfd.de 

March 7, 2014, 15:59 

#353  
Super Moderator
Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
Posts: 9,635
Blog Entries: 39
Rep Power: 99 
Quote:


March 7, 2014, 16:38 

#354  
Senior Member
Tobias Holzmann
Join Date: Oct 2010
Location: Leoben (Austria)
Posts: 1,501
Blog Entries: 6
Rep Power: 25 
Quote:
I wrote with Alberto last week
__________________
Best regards, Tobias Holzmann Some interesting OpenFOAM tutorials and videos on www.Holzmanncfd.de 

March 8, 2014, 04:08 

#355 
Senior Member
Tobias Holzmann
Join Date: Oct 2010
Location: Leoben (Austria)
Posts: 1,501
Blog Entries: 6
Rep Power: 25 
Hi all,
just one question to you. With the NASA polynomials it is possible to calculate the heat capacity, entropy and enthalpy of the species X on different temperatures. We can do the same for the transport properties but where can I find the polynomials for the calculation? At the moment I am analysing the flameletcreator tool from Alberto Cuoci et. al. but the polynomials which are given in the output files are still modified so that it is not possible to figure out what prefactors are in the eqn. I will try to search again today evening but maybe someone of you knows the answer/link/literature ... 

March 19, 2014, 04:58 
Fluctuation in Zvar in swirl flame

#356 
Member
vishal
Join Date: Mar 2013
Posts: 56
Rep Power: 5 
Greeting all,
I simulate the SM1 sydney swirl flame using all modification as suggested by tobi and variance equation off mode. But there is lot of fluctuation in Zvar . https://www.dropbox.com/s/qc85it4m42jgzmd/Zvar.pdf Can you suggest something regarding this issue ?? Regards, Vishal 

March 24, 2014, 07:29 
Regarding Bluff Body flame simulation

#357 
Member
sonu
Join Date: Jul 2013
Location: delhi
Posts: 91
Rep Power: 5 
Greeting all ,
I was trying to simulate bluff body flame (sandia HM1) from last few days using the flameletSimpleFoam solver.But there is some issues . i am attaching some of the contour plots of velocity and temperature after Time= 40000 . Plz somebody suggest me whats wrong in my case , if needed i can send my case files , Thanks , Regards , Sonu 

March 24, 2014, 07:49 

#358 
Senior Member
Tobias Holzmann
Join Date: Oct 2010
Location: Leoben (Austria)
Posts: 1,501
Blog Entries: 6
Rep Power: 25 
Hi,
I know that Alberto et. al. do this simulation with very accurate solution. Please try to use the "not modified" and "original" code of the libOpenSMOKE tool and let us know if you will get better results. The official tool is available for 1.7.x and 2.0.x at Brunos github. Maybe I made a mistake in converting it to 2.2.x  i just made the validation with COH2N2 flame. Regards Tobi 

March 25, 2014, 01:31 

#359 
Senior Member
Bobi
Join Date: Oct 2012
Location: Chicago, Illinois
Posts: 342
Rep Power: 6 
Greetings all
@ Sonu The simpleFoam solver does not have any problems (If you look at this thread pages, you will see that different bluffbody stabilized flames are simulated with this solver). You must have a problem with your PDF tables or schemes (unstable ones). Try using schemes proposed by Tobi or in case of using Alberto's original code, his schemes, you will get reasonable results. Bobi 

March 25, 2014, 02:43 

#360 
Member
sonu
Join Date: Jul 2013
Location: delhi
Posts: 91
Rep Power: 5 
Greeting bobi ,
i wll check both things PDF table and the schemes and then let you know .. Thanks for suggesting Regards , sonu 

Thread Tools  
Display Modes  

