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-   -   how to improve convergence for fine mesh E-E model for fluidized bed? (http://www.cfd-online.com/Forums/fluent/102160-how-improve-convergence-fine-mesh-e-e-model-fluidized-bed.html)

bitsfluent May 24, 2012 02:12

how to improve convergence for fine mesh E-E model for fluidized bed?
 
the convergence is 1e-8s! and takes ages (literally) :( to get 0.1s of simulation- its a solid bed with freeboard above and gas velocity inflow bc at bottom.
even 1e-7,1e-6s time step would make a huge difference. any tips??

sadeghsalehi October 7, 2012 17:01

How many phases are there in your simulation? what is the number of transport equation which should being solved and the degree of coupling? hence, you should enter 1e-3 for absolute criteria of continuity, and enter 1e-5 for time step at first simulation, before this procedure you must simplify your problem.

Maryam.SUT October 9, 2012 14:39

Quote:

Originally Posted by sadeghsalehi (Post 385378)
How many phases are there in your simulation? what is the number of transport equation which should being solved and the degree of coupling? hence, you should enter 1e-3 for absolute criteria of continuity, and enter 1e-5 for time step at first simulation, before this procedure you must simplify your problem.


hi
i am simulating a fluidized bed. i have a problem. there is reversed flow at outlet boundary and the solution does not converge. how can i solve this problem.
Thank you in advance

sadeghsalehi October 9, 2012 15:34

be sure the gravity is activated

Maryam.SUT October 9, 2012 15:39

Quote:

Originally Posted by sadeghsalehi (Post 385809)
be sure the gravity is activated

thanks alot
i activated gravity in general setting
should i active gravity in operating condition?

Maryam.SUT October 9, 2012 15:47

Quote:

Originally Posted by sadeghsalehi (Post 385809)
be sure the gravity is activated

it seems that you have enough experience in fluidized bed modeling. may I have your E-mail address?

sadeghsalehi October 9, 2012 15:52

yes it must be activated in operating condition panel

nkme2007 October 10, 2012 05:45

Hello All,

I want to do analysis of heat transfer from water flowing through pipes submerged inside concrete. I am modelling in GAMBIT and wish to analyse it on Ansys FLUENT.

Can anybody help me out, how to model and simulate?

Does any tutorials exist?


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