[Gioralex]

Hello Foamers,


I would like to know the meaning of ignition strength in combustionProperties in kivaTest


tutorial. What does it mean ? How does it influence the results ? What's the correct



value ?

Any help is appreciated.

Thank you in advance, regards

[dlahaye]

Combustion is started by ignition source. The amplitude of this source is the ignition strength. Its value is application dependent.

[Gioralex]

Originally Posted by dlahaye

Combustion is started by ignition source. The amplitude of this source is the ignition strength. Its value is application dependent.

Hi dlahaye,


thanks for the rapid answer. I'm using XiEngineFoam to simulate a premixed combustion of a methane-air mixture in engine which is very similiar to the one of kivaTest. The compression ratio is 10. I've created my own structured mesh with Hypermesh (Altair). So how do I know the correct value of the ignition strength for my case? For example in the kivaTest tutorial it is set to 4.


Thanks in advance for any help. Regards

[dlahaye]

Unable to answer this. Ask around in environment in which your problem originates. Or look into publication on engineFoam.

[Gioralex]

Hello Foamers,


I moved on and now I have some new questions about XiEngineFoam:


1. As you can see from the files in the attachment, I changed the fuel from isoOctane to methane. I used the tool adiabaticFlameT and from the thermo.log file I have found the correct values of the janaf coefficients to put in the thermophysicalProperties for fuel, oxidant and burntProducts. Is it correct ?



2.I have also found in literature the Sutherland coefficients As and Ts for the transport for fuel and oxidant but not for the burntProducts. How can I determine this values ? How do they change the results ?


3.I have run the simulation of a premixed stochiometric combustion with XiEngineFoam. If I would change the equivalence ratio what I have to do ? Is it enough to change the equivalenceRatio in the combustionProperties or I have to change something else in thermophysicalProperties ?


Thank you in advance for your support. It means a lot for me and for my thesis.

Any help is appreciated


Giorgio

[dguleryuz]

Originally Posted by Gioralex

Hello Foamers,


I moved on and now I have some new questions about XiEngineFoam:


1. As you can see from the files in the attachment, I changed the fuel from isoOctane to methane. I used the tool adiabaticFlameT and from the thermo.log file I have found the correct values of the janaf coefficients to put in the thermophysicalProperties for fuel, oxidant and burntProducts. Is it correct ?



2.I have also found in literature the Sutherland coefficients As and Ts for the transport for fuel and oxidant but not for the burntProducts. How can I determine this values ? How do they change the results ?


3.I have run the simulation of a premixed stochiometric combustion with XiEngineFoam. If I would change the equivalence ratio what I have to do ? Is it enough to change the equivalenceRatio in the combustionProperties or I have to change something else in thermophysicalProperties ?


Thank you in advance for your support. It means a lot for me and for my thesis.

Any help is appreciated


Giorgio

Hello Giorgio,

I am trying to use XiFoam. Could you please share how did you use the tool adiabaticFlameT?

Thanks and regards.