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Questions on DPM model..please

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Old   October 6, 2010, 03:16
Default Questions on DPM model..please
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Panos
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Goodmorning

Im simulating the flow of air in a channel coupled with heat transfer from the walls to the air stream. Now i would like to insert a mass flow. The volume fraction is les than 0.01 Vsolid/Vair so i selected the DPM model. Its the first time im using this model so i wanna ask about the convergency or any strategies to have a solution. How can i check the solution of the DPM?
In addition i would like to activate the walls radiation. In the previous simulations (without solid particles) i assumed air as transparent media so radiation didnt effect the results (standard wall temperature). No radiation will effect the solids temperature. I was thinking of activating radiation after i simulate the solids movement. Is this right? Do you agree that S2S radiation model is good for my case or maybe DO model?

Thank you in advance
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Old   October 6, 2010, 11:01
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sreenivasa rao gubba
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Hi

what type of solid particle are they? such as inert or reacting etc. If they are inert, I would not think radiation will have much impact on them and viceversa. However, if the particles are reacting, you need to think of radiation aprior to DPM.

You can get postprocess DPM from reports. If you tell me what you exactly looking for, I may shed more light on it.

Sree
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Old   October 6, 2010, 14:44
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Hello Sree and thank you for your interest

My particles are inert..lets say its sand. i have no reaction but only heat of the particles. I wanted to know the temperature ,velocity and the residence time of the particles in the tube . I wanted to add radiation because in some cases there is high difference between air and walls temperature (when flow is high). In this case , due to radiation it is expected that particles will raise the air temperature.

If i wanna couple the wall radiation effect , it would be better to do it before solving the DPM?
What would you recommend me

Thank you in advance
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Old   October 7, 2010, 06:26
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sreenivasa rao gubba
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Hi

Yes, you need to do your radiation first for this case. Once you have decent convergence, you can initiate DPM in "Graphics & Animatons>particle tracks>particle variables" if it is one-way coupling. If you are considering two-way coupling, you need to set when the injections will release in "models>discrete phase" by choosing after how many continuous iterations do you want to inject the particles.

If you think even your inert particles does effect (adding energy source trhough radiation) continuous phase, then you should choose two-way coupling. Otherwise, it is not really nessasary.

Just check wether you can switch on or not "Particle Radiation Interactions" in DPM for inert particles or not. If it lets you to switch, that would take care of the effect radiation.

Hope this helps.
Sree
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convergence, discrete phase model, s2s radiatiation model

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