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-   -   Unsteady DPM (http://www.cfd-online.com/Forums/fluent/39610-unsteady-dpm.html)

Johnny February 13, 2006 09:41

Unsteady DPM
 
I have modelled a simple 1 litre mixing vessel. The fluid is water and it is mixed by a 2 blade impeller. The vessel has no inlet or outlet. The model is steady.

I want to model the trajectory of one small particle. Section 23.1.3 of the html manual states that the unsteady-particle discrete phase model is capable of modeling continuous suspensions of particles.

I have set an injection. I have set injection start and finish times to 0 (as injections with start and stop times set to zero will be injected only at the start of the calculation).

Under the DPM panel, I have checked the box for Unsteady Particle Tracking, and have set the Particle Time Step Size to 0.01s and the number of steps to 1000.

I have not checked "Interaction with Continuous Phase".

I have gone to the Display Particle Tracks Panel, selected the relevant injection and clicked Display. The grid is displayed, but no particle trajectory is displayed. It appears as though no particle is injected. When I ask for a plot of trajectory coloured by Particle ID, the range given is -1e+20 to +1e+20.

Please advise as to what I need to do in order to draw the trajectory of a particle using the unsteady DPM.


Lourival February 22, 2006 13:43

Re: Unsteady DPM
 
I had the same problem. To have the particle in the fluid is necessary to set the start time and the end time, because this time is related to the current time of the problem so if you set 0 for both it means that you want that the FLUENT inject particles between 0 and 0. If you want one particle, so you need to set the start 0 and end to the TIME_STEP (s) of the flow.

Hope that it works

Lourival


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