[parisa-]

Hi everyone,

I need to know how to use DPM in FLUENT to find the exposure time of fluid elements on the liquid surface of a VOF modeling in a stirred tank reactor. I have transient simulations so I need to use the unsteady particle tracking just to see how the fluid elements are moving in the tank and find the surface exposure time. So I set a few massless injections like injections from a surface that I have defined. I also set the particle history data in the calculation activities panel to generate a file every time step. However, I don't know how to open the generated file which is .fvp or .mpg or .mcl. And in the particle track panel it is not possible to track any particle when the unsteady particle tracking option is on.
I should also mention that it is a sliding mesh and the turbulence model is LES.
I have read the discrete phase modeling part in the user's guide but it still is not enough help. Can anyone help me if you have enough info about using DPM or if there is a tutorial I can read about this?
Thanks

/Parisa

[aliyah]

Hello Parisa,
Basically my simulation work is very much related to what you are doing. I have encountered the limitations you have mentioned. Unfortunately i have not yet figured out how to tract the particles every time step while calculation is on-going. Particles can only be tracked in every data file so what i did is save the data files at certain time steps. However this is very tedoius job if you want to tract particles in a longer time.
If you figured out how to do it, can you please share it?
If not yet, we can start discussing it and hope to find solution for this matter.
I'l wait for your reply.
Thanks,
Aliyah

[parisa-]

I found the problem. When you do the DPM particle tracking for transient simulation, you have to set a time for start and stop releasing the particles in the system. So when you set the injections, at the same place that you set the location of the injections, you can set the time for injections also. For example if you have been running the simulation for 3s, I mean if the flow time which is shown at the end of each time step calculation, is 3s then the starting time for the injection is 3s and the stop time is the next time step (if you wish to follow only the fluid pathlines I think one time injection of particles is enough). For example if your time stepping is 0.001 s then the start time is 3 and the stop time is 3.001. I hope it helps you, at least this was the problem I had.
Good luck
/Parisa