Author Topic: DPM Injections  (Read 1882 times)

Offline lakhi

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DPM Injections
« on: July 11, 2012, 05:38:19 PM »
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Using DPM, if I want to inject, say, 2000 particles from inlet and simulate to get the results, what I have to do in FLUENT 14?
How to keep track of the particle positions?
There is an option in FLUENT "Injection-Type: group", where the variables, namely: x-,y-, and z-positions are required for first point and last point. What are these first point and last points.
For surface type injection, we have, start time and stop time. I guess there are injection time (discrete phase injected for 5 sec) in the continuum phase. If this is true, how does FLUENT inject discrete phase? I mean if I choose "start time = 0" and "stop time = 5 sec", how will FLUENT react to these time variables. I think it won't inject desirable number of particles.
I'm not very familiar with DPM, so please explain me in details.
« Last Edit: July 11, 2012, 05:42:17 PM by lakhi »

Offline william

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Re: DPM Injections
« Reply #1 on: July 11, 2012, 06:32:25 PM »
Please see Fluent manual for instructions on how to use the DPM model. Link below:

https://www.sharcnet.ca/Software/Fluent12/html/ug/node666.htm


Offline RodriguezFatz

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Re: DPM Injections
« Reply #2 on: July 12, 2012, 02:31:55 PM »
To the "surface injection" questions: This is not explained satisfyingly in the manuals.  >:(
Fluent injects one particle in each numerical cell that shares a face with the surface you chose. So let's say your velocity inlet has 1200 boundary cells - then Fluent injects 1200 particles.
Now, in the "Discrete Phase Model" dialog box, you will set the "Inject particles at ..." e.g. "Fluid Flow Time Step" - meaning Fluent will inject that (1200) amount of particles every time step of your transient solver. Start and stop-time then will tell Fluent when (by means of computational time of the solver) to start and when to stop injecting particles every time step.
The total weight of all particles is the mass flow rate you choose (in the Set Injections dialog box) times the time step. This will be shown each time step in the Fluent terminal: "Injecting 1200 particles with mass 0.034 at t=0.01".

Offline lakhi

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Re: DPM Injections
« Reply #3 on: July 14, 2012, 04:55:35 AM »
Thanks RodriguezFatz.

I'll try the same. Hope now I'll get some results.

Offline lakhi

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Re: DPM Injections
« Reply #4 on: July 14, 2012, 05:28:13 AM »
Hi william

Thanks for your effort too !