Eulerian lagrangian model
Hi
Can anyone help me in telling me how can i set up a eulerian lagrangian model in fluent. Thanks in advance SHK |
You have to use Discrete phase models available in Fluent . The continuous phase is solved like an continuum and the secondary phase/discrete phase is solved through lagrangian method.
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Cfd
Kindly tell me the steps to put a eulerian langrangian model in fluent.
I am not been able to interlink the secondary phase of the DPM model with the secondary phase of the eulerian model kindly tell me how to do that Thanks SHK |
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After loading the mesh file, go to the models. Select your turbulence model then select Discrete Phase. If you want the particles to exchange momentum with the continuous plahse than select the option "interaction with continuous phase". Now click the injections button. Then click create button. Add your particle properties and the way particles are injected. You may have these via spray cone, single stream etc... Specify the position of injector (x, y and z) in the same window. Also specify the number of particle streams. That should be it. You can specify the physical properties of the injected particles in the Materials menu. |
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Hello
Thanks for the reply I have one clarification. While using the Eulerian-Langrangian Model is it so that we have to on the eulerian model from define>model>multiphase>eulerian and then on the dpm model as discussed above or Dpm itself takes care of the eulerian and Lagrangian framework of the calculation. and Is that possible to use both eulerian and dpm model at the same time in fluent if yes how?? Thanks SHK |
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Thanks for the reply but my question remains the same??
Can we use both both DPM and multiphase eulerian model at the same time.If yes how?? Thanks Shk |
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hi mali
is discrete phase (particles), turbulence always? |
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Hi, I have the same question, any one can help me please |
Have you tried using the multiphase Eulerian model and then enabling the DPM as well to see for yourself? I can't think of any reason that DPM couldn't be used with the multiphase model; especially if you're only concerned with one-way coupling.
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By the way, I used two way coupling, what is the difference it makes compared to one way coupling? Thanks |
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I have problem when I add injection! Actually i am interested to have injection so that i can see particle track. can you help me please |
What do you mean by "injection"? If you don't specify an injection for the DPM, then you're not using the Lagrangian model (or DPM) at all.
One-way coupling is where the particles are influenced by the fluid; for example, the particles would tend toward the fluid velocity due to drag (and the speed of which is a function of the particle relaxation time). Two-way coupling also includes the influence of the particles on the fluid. Lastly, four-way coupling also considers the particle-particle interactions. |
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Thanks, |
What didn't converge when you specified the injections? What initial conditions, mass flow rates etc have you specified for your injection streams?
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Specifically: did the solver crash/stop during the DPM calculations or the continuous phase iterations? What error was displayed?
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You can specify how many DPM iterations the solver does until it stops (the default is 500). If the particle stream hasn't escaped the domain within this number of iterations then this stream would be incomplete (finishes partway through the domain).
What path lines are you generating (show us a figure) and what are you expecting (show us another figure)? |
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Attachment 38104 for particle track the streams are incomplete! i will also provide fig for this |
Where is the mesh (display the outline only to avoid cluttering) to see the overall shape of the domain? What path lines are you expecting?
You've just quoted my post on how to solve the "incomplete" particle tracking issue, please read carefully... |
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I think i do not understand your question clearly, but the max number of steps for tracking is 500.. this is the path line i expect to seeAttachment 38110 and this my particle track which i said it is incompleteAttachment 38111 and this is the path line i got with outline mesh ( i am not sure if u were asking me this!)Attachment 38112 |
If the particles are incomplete at the end of the simulation then that would indicate they require more steps until they leave the domain.
Your task: change the maximum number of steps for tracking from 500 to say 50,000. |
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Would you please tell me if i just use eulerian approach can it consider the brownian motion? |
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Tackle one issue at a time: have you tried a tracking simulation after increasing the maximum number of steps for tracking to remove the "incomplete" particle problem?
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I got the message that the temperature is limited to..and when i remove the limit form temperature the outlet temperature the software gave me was out of range. Can you help me how to solve it? |
Have a read of the Fluent FAQ section on convergence issues and we'll go from there.
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I read this part it said the momentum and pressure should be 0.6 and 0.1. I changed mine (pressure 1 and momentum 0.7) to these numbers it becomes worse than before, it gave me the reverse flow message and then increasing sweep and then it said no divergence. these errors came in the first iterations!! it also said to set k and eps to 0.4 which i could not find out where should i set these. |
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2. does eulerian consider interaction between particles? or just eulerian with lagragian could consider this interaction? Thanks |
1. When did this temperature limited error arise, did the simulation previously work and then did you change something?
2. The one- or two-way coupling between the discrete phase (Lagrangian) and continuous phase (Eulerian) dictates the interaction between particles, or lack thereof. Both of these options are available in the DPM of Fluent. Have a read of the "Modeling Discrete Phase" chapter of the user's guide. |
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2. As it gave me good results with eulerian i preferred to work with eulerian but i was wondering if particles interaction (brownian motion) could be considered in eulerian model?! I know i can use two way coupling but need to be sure eulerian consider solid particles interactions. I read it but still need to know. please give me your opinion. Thanks |
1. Terminology: you're not using DPM if there are no injections. Ensure you're not exceeding the limits of DPM (particle volume fraction etc).
2. I'm familiar with the DPM but not the Euler-Euler approach of modelling particles in a fluid. If your simulations are working in the Eulerian reference frame, then that's great, but you'll need to check the user's manual (or theory guide) for checking how it treats diffusion / Brownian motion. |
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Would you please tell me why i got this "temperature limit " error and how can i fix it? |
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1. i put 3 particles for the cone , i expect i see 3 streams. why i see just 1 stream? 2. i need to see the location of each particle. i mean i want to find out particles motion. can u tell me how should i set particle track to display it for me? i could not find any option in particle track that display the location of each of these 3 particles! |
Have a read of the user's guide and tutorials on visualising particle streams; all of your questions are answered there in step by step detail.
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