# how to improve convergence for fine mesh E-E model for fluidized bed?

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 May 24, 2012, 02:12 how to improve convergence for fine mesh E-E model for fluidized bed? #1 New Member   cfd Join Date: Oct 2011 Posts: 6 Rep Power: 7 Sponsored Links 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??

 October 7, 2012, 17:01 #2 New Member   mohammad sadegh Join Date: Apr 2011 Posts: 4 Rep Power: 8 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.

October 9, 2012, 14:39
#3
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Maryam
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Quote:
 Originally Posted by sadeghsalehi 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.

 October 9, 2012, 15:34 #4 New Member   mohammad sadegh Join Date: Apr 2011 Posts: 4 Rep Power: 8 be sure the gravity is activated

October 9, 2012, 15:39
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Maryam
Join Date: Sep 2012
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Quote:
 Originally Posted by sadeghsalehi be sure the gravity is activated
thanks alot
i activated gravity in general setting
should i active gravity in operating condition?

October 9, 2012, 15:47
#6
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Maryam
Join Date: Sep 2012
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Quote:
 Originally Posted by sadeghsalehi be sure the gravity is activated
it seems that you have enough experience in fluidized bed modeling. may I have your E-mail address?

 October 9, 2012, 15:52 #7 New Member   mohammad sadegh Join Date: Apr 2011 Posts: 4 Rep Power: 8 yes it must be activated in operating condition panel

 October 10, 2012, 05:45 #8 Member   Tamil Nadu Join Date: Oct 2012 Posts: 44 Rep Power: 6 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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