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Troubles with the dpm model

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Old   February 23, 2009, 09:36
Default Troubles with the dpm model
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Marco Antonelli
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Hi, I'm Marco Antonelli and I am researcher at the University of Pisa.

I set up a cluster for parallel computing using Fluent 6.3 and I'm simulating the injection of gasoline inside an engine cylinder. When I used a single pc it ran all ok, but since I've been trying using this cluster, I've this trouble with the injection: after some time steps, the calculation is blocked at the dpm injection advance and does nor proceed, neither giving any error.

Anyone had the same trouble than me?

Thanks

Marco
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Old   February 24, 2009, 16:40
Default Re: Troubles with the dpm model
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John S.
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Are you running a multiphase simulation?
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Old   February 25, 2009, 03:37
Default Re: Troubles with the dpm model
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Marco Antonelli
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My simulation is a discrete phase one. I'm injecting gasoline inside an engine cylinder.

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Old   February 25, 2009, 12:23
Default Re: Troubles with the dpm model
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John S.
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The reason I asked, to quote the 6.2 manaul..

"When tracking particles in parallel, the DPM model cannot be used with any of the multiphase flow models (VOF, mixture, or Eulerian { see Chapter 23: Modeling Multiphase Flows) if the shared memory option is enabled (Section 22.11.9: Parallel Processing for the Discrete Phase Model). (Note that using the message passing option, when running in parallel, enables the compatibility of all multiphase ow models with the DPM model.)"
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Old   February 26, 2009, 03:29
Default Re: Troubles with the dpm model
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Marco Antonelli
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No, any of these model was used. Moreover, the message passing option is currently used. The strange fact is that the calculation start, but stops after a random number of time steps without an apparently cause.

bye

Marco
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Old   February 28, 2009, 20:08
Default Re: Troubles with the dpm model
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giovanni franchello
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Do you use wall-film model ? The same happens also to me
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Old   March 3, 2009, 10:24
Default Re: Troubles with the dpm model
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Marco Antonelli
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Yes, I do. I'm trying to change some parameters about numerics, but I've still got very few results...

If I'll discover something interesting, I'll post it.

bye

Marco
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Old   March 3, 2009, 12:12
Default Re: Troubles with the dpm model: collision probl ?
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Gian
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I am simulating injection of liquid ammonia (tb=-33 Deg) in tha atmosphere (air + water vapour, 80% humidity). The solver is pressure-based, usteady. Problem time 900 sec, time step=0.25 sec, 150000 cells, 6 node parallel computer. DPM: injected 5 parcels per particle time step=0.05 sec. coupled, unsteady. Boundary: wall-film. I had very big problems: temperature & pressure out of the limits, dpm concentration > 10000kg/m3, extreme jumps in the mass sources, evaporation of droplets with temp. below dew point (??), crash. Despite I eliminate problems in crashes (re-writing the mass & heat transfer routines), FLUENT enters in an infinite loops after the message Advancing DPM Injection ...

I remove the problem by switching off the droplet-collision option !!!

Try it. Gian

PS: now I use wall-jet because with wall-film I had problems in parallel processing like "lost x particles in node y" and consequent mass error

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Old   March 3, 2009, 12:55
Default Re: Troubles with the dpm model: collision probl ?
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Marco Antonelli
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However, coalescence is a very important matter while simulating injections (especially gasoline injection)...
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Old   June 14, 2010, 03:48
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Shao Senlin
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I have the same qusetion, how did you solve it?
think you!
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Old   December 7, 2010, 10:18
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Marta Lazzarin
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Hi All! Is the wall-film model compatible with combustion models in Fluent?

Thanks a lot in advance!

Marta
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