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-   -   HELP :AVL FIRE Engine combustion convergence problem (http://www.cfd-online.com/Forums/avl-fire/85751-help-avl-fire-engine-combustion-convergence-problem.html)

vikram29586 March 5, 2011 23:39

HELP :AVL FIRE Engine combustion convergence problem
 
Dear All Members,

Iam using latest AVL fire 2010 (v9.1) version for simulating engine combustion. Detaiked combustion chamber meshing was done using inbuilt moving mesh tool ,. I get SOLUTION DIVERGED message just after few iterations.
Th following are the inputs
1 . k-zeta-f and turbulent flame speed closure model and spark ignition model
2. Initial Turbulent kinetic enrgy and length scale based on the actual values

I reduced time step to 10e-6 , changed differencing scheme to upwind,reduced under relaxation factors but still getting same message.

moving meshing was created using inbuilt Fame engine plus tool, at the end of meshing process i get a message that the mesh can be used for calculation .
I tried to use a mesh of a simple geometry without crevices n liners, it works well n i get the result as well.
Please help me :(

Thanks in advance

Regards
Vikram

hbganguly July 26, 2011 05:21

Hi...i am just trying to understand the pros of AVL fire though am familiar with AVL Boost...
can any1 throw some light on AVL fire? so that i can link the boost engine combustion models in AVL fire or what not... what stuff AVL Fire can do where Boost cant|????

doki July 26, 2011 09:15

well the case should be examined carefully, but I think there might be some problems in the setting of the solution, especially boundary and initial conditions and/or URFs. :)

songwukong November 1, 2011 12:11

Hi guy, have you solved your problem after there months?
I am interested in your things.
In CFDonline the avl-fire users are minor, maybe we can do more communication about fire incylinder calculation, to benefit both.

Regards
Song

blyashwanth November 21, 2011 04:53

Divergence during combustion simulation on AVL FIRE
 
Hello
I do have the same problem.
I have managed to make the solver complete a crank angle of 870 deg.
Now the solver is started to diverge.

Well one needs to use K - epsilon and not KZF model.
Try solving it and lemme know

rezahemmat1985 January 16, 2012 03:50

salam
 
salam doki
I am master student of internal combustion engine and I am simulating the single phase boiling in a bottom heated rectangular duct . I used the defalt values for convergence criteria and under-relaxation factors , but the results devaiate alot with the experimental ones are so much . what convergence criteria and under-relaxation factors do you reccomand to use ?

rezahemmat1985 January 25, 2012 04:13

hi dear Virkram
I am simulationg single-phase boiling in AVL Fire , but unfortunately the results diverged . I wanna to make my model(duct) in CFX and import it in AVL Fire, can you tell me how can I import my CFX-built model with its boundaries into AVL Fire?does the CFX-built boundaries would be recognized in AVL FIre?tell me how can I makemy model and its boundaries in a software(like CFX,ICEM,...) and import it in AVL Fire ?plz be in contact with me via E-mail : reza_hemmatdj@yahoo.com

sena March 1, 2012 09:00

Hi All,

I have created a model in Avl Boost and now I want to obtain 3d results with avl fire v2010 but I don't have any tutorials about it except Avl fire help.If you have some tutorials,can you send me? I don't know how I can run the programme,yet.Please help me. My email address is x.learner.y@gmail.com

Sena

sena April 12, 2012 17:45

Quote:

Originally Posted by vikram29586 (Post 298083)
Dear All Members,

Iam using latest AVL fire 2010 (v9.1) version for simulating engine combustion. Detaiked combustion chamber meshing was done using inbuilt moving mesh tool ,. I get SOLUTION DIVERGED message just after few iterations.
Th following are the inputs
1 . k-zeta-f and turbulent flame speed closure model and spark ignition model
2. Initial Turbulent kinetic enrgy and length scale based on the actual values

I reduced time step to 10e-6 , changed differencing scheme to upwind,reduced under relaxation factors but still getting same message.

moving meshing was created using inbuilt Fame engine plus tool, at the end of meshing process i get a message that the mesh can be used for calculation .
I tried to use a mesh of a simple geometry without crevices n liners, it works well n i get the result as well.
Please help me :(

Thanks in advance

Regards
Vikram

Hi Vikram,

I am trying to learn Avl Fire 2010.But I don't have any tutorials.Could you send me some tutorials? I have a little time to finish my masters,but couldn't even run the programme.Please help me.

Looking forward to your reply

Sena

saikrishna12 April 18, 2012 13:21

@vikram29586

I have been working on AVL fire for combustion simulation of DI Diesel Engine.

The first thing to check if the solution diverges is ur mesh. If ur moving meshes are perfectly made and appended, a dummy run must happen smoothly(without strucking).

If u r able to run the solver successfully with simple geometry and getting diverged solution with crevices, then the "selections" made might hav an error.

If everything is fine with meshing then we shall discuss on input data in solver steering file
:)

saikrishna12 April 18, 2012 13:49

@hbganguly

AVL Fire is a 3D CFD simulation software used for combustion analysis, analysis of intake ports and manifolds, cooling jackets etc.
Results from AVL Fire combustion simulation include Emissions(NO,CO,HC,CO2,Soot,H20 etc), rate of heat release, pressure, temperature, turbulent kinetic energy, equivalence ratio etc,
combustion simulation videos can be saved and we can study the combustion pattern and spray pattern, turbulence, swirl etc.

Where as AVL boost is 1D simulation software whose results can be integrated with AVL Cruise and Fire for further analysis.(Cannot explain in detail since i never worked on Boost)
For eg: we can know that temp at piston head is 450 K from Boost and this result can be used in Fire for further analysis(just a vague guess)

sena April 18, 2012 14:06

Hi Saikrishna,

I am trying to learn Avl Fire.I am trying to run the example which I have downloaded pdf from avl website.Its name is 02_CFD-Getstarted_v2010_04_ESE_Tutorials.I have already entered the same datas with it.It is still continueing to run on my laptop.But, when I wanted to see engine specific output data,I couldn't see air fuel ratio,IMEP,ındicated power,indicated specific power,indicated specific torque,indicated torque and injected fuel mass.I see that all of them are 0.00E+000.Where do we enter these datas to Fire? Or does it calculate them?I am looking forward to your reply.Please help me.




Quote:

Originally Posted by saikrishna12 (Post 355452)
@hbganguly

AVL Fire is a 3D CFD simulation software used for combustion analysis, analysis of intake ports and manifolds, cooling jackets etc.
Results from AVL Fire combustion simulation include Emissions(NO,CO,HC,CO2,Soot,H20 etc), rate of heat release, pressure, temperature, turbulent kinetic energy, equivalence ratio etc,
combustion simulation videos can be saved and we can study the combustion pattern and spray pattern, turbulence, swirl etc.

Where as AVL boost is 1D simulation software whose results can be integrated with AVL Cruise and Fire for further analysis.(Cannot explain in detail since i never worked on Boost)
For eg: we can know that temp at piston head is 450 K from Boost and this result can be used in Fire for further analysis(just a vague guess)


saikrishna12 April 19, 2012 03:22

Quote:

Originally Posted by sena (Post 355453)
Hi Saikrishna,

I am trying to learn Avl Fire.I am trying to run the example which I have downloaded pdf from avl website.Its name is 02_CFD-Getstarted_v2010_04_ESE_Tutorials.I have already entered the same datas with it.It is still continueing to run on my laptop.But, when I wanted to see engine specific output data,I couldn't see air fuel ratio,IMEP,ındicated power,indicated specific power,indicated specific torque,indicated torque and injected fuel mass.I see that all of them are 0.00E+000.Where do we enter these datas to Fire? Or does it calculate them?I am looking forward to your reply.Please help me.

Hi sena,

I am simulating combustion using AVL Fire CFDWM itself and i do not have ESE module activated.
From AVL Fire, we cannot get the direct results which were mentioned by you. If ESE gives the values directly specified by you and if it is showing 0.0 then either 1. u hav not activated the spray, or
2. the iterations still didn't reach the crank angle where fuel is injected
In AVL Fire,
Air fuel ratio can be calculated from equivalence ratio which is obtained from 2D Results. Power can be calculated from Rate of heat release (J/deg) values. Plot a graph between rate of heat release and crank angle and calculate the area of the graph. That gives the power. Injected fuel mass has to be given as input in solver steering file and can be checked whether correct mass is injected or not from "Spray:Liquid mass injected" column in 2D results.

and by the way, how could you get tutorial from avl website...can u send me the link

sena April 19, 2012 04:48

Hi Saikrishna,

Thank you for your reply :).Maybe as you said,my iterations didn't reach to angle which fuel is injected.I will wait for it.I can download them with my user name and password from avl website.If you don't have a password,you can not download them.But if you want,I can download for you.Which documents do you want?

Sena



Quote:

Originally Posted by saikrishna12 (Post 355536)
Hi sena,

I am simulating combustion using AVL Fire CFDWM itself and i do not have ESE module activated.
From AVL Fire, we cannot get the direct results which were mentioned by you. If ESE gives the values directly specified by you and if it is showing 0.0 then either 1. u hav not activated the spray, or
2. the iterations still didn't reach the crank angle where fuel is injected
In AVL Fire,
Air fuel ratio can be calculated from equivalence ratio which is obtained from 2D Results. Power can be calculated from Rate of heat release (J/deg) values. Plot a graph between rate of heat release and crank angle and calculate the area of the graph. That gives the power. Injected fuel mass has to be given as input in solver steering file and can be checked whether correct mass is injected or not from "Spray:Liquid mass injected" column in 2D results.

and by the way, how could you get tutorial from avl website...can u send me the link


sena April 19, 2012 04:55

And I would ask you if we could only simulate combustion with Avl Fire when both of the valves were closed.Or can we also simulate it when the valves are open?

Quote:

Originally Posted by sena (Post 355556)
Hi Saikrishna,

Thank you for your reply :).Maybe as you said,my iterations didn't reach to angle which fuel is injected.I will wait for it.I can download them with my user name and password from avl website.If you don't have a password,you can not download them.But if you want,I can download for you.Which documents do you want?

Sena


saikrishna12 April 19, 2012 13:42

@sena

I'll definitely ask u when i need some tutorials.
The simulation is done between IVC and EVO

sena April 19, 2012 15:23

Thank you very much for your reply and I will help you when you need them :)

Sena


Quote:

Originally Posted by saikrishna12 (Post 355694)
@sena

I'll definitely ask u when i need some tutorials.
The simulation is done between IVC and EVO


sena April 19, 2012 16:05

But when we want to simulate whole of the cylinder (IVO,EVC,IVC,EVO),which version of Fire should I use? I heard about Fame but which Fame? I see that FAME Hexa,FAMETetra,FAMETopo,FAMEWrapper..Which one of them can we simulate whole of the cylinder?


Quote:

Originally Posted by sena (Post 355708)
Thank you very much for your reply and I will help you when you need them :)

Sena


sena May 29, 2012 11:02

Dear Saikrishna

I am still trying to obtain some simulation results with Avl Fire Ese Diesel.I am trying to decide my mesh number,so I firstly tried both 175000 meshes and 57000 meshes for the same case.If I donít see any differences between them,I will do my other runs with 57000 meshes faster.But,I would ask you one thing about it. How can I compare the velocities or pressures or anything else along a line? For example; can I see the velocities at the center of the piston along center at different points? I don't know how I can do this.Please help me.

Sena




Quote:

Originally Posted by saikrishna12 (Post 355694)
@sena

I'll definitely ask u when i need some tutorials.
The simulation is done between IVC and EVO


Ayoshi June 6, 2012 16:02

Quote:

Originally Posted by sena (Post 355712)
But when we want to simulate whole of the cylinder (IVO,EVC,IVC,EVO),which version of Fire should I use? I heard about Fame but which Fame? I see that FAME Hexa,FAMETetra,FAMETopo,FAMEWrapper..Which one of them can we simulate whole of the cylinder?

hi sena , use fame engine plus .


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