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

bitsfluent · May 24, 2012, 02:12

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

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

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

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?

May 24, 2012, 02:12	how to improve convergence for fine mesh E-E model for fluidized bed?	#1
bitsfluent New Member cfd Join Date: Oct 2011 Posts: 6 Rep Power: 14	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??

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October 7, 2012, 17:01		#2
sadeghsalehi New Member mohammad sadegh Join Date: Apr 2011 Posts: 5 Rep Power: 15	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, 15:34		#4
sadeghsalehi New Member mohammad sadegh Join Date: Apr 2011 Posts: 5 Rep Power: 15	be sure the gravity is activated

October 9, 2012, 15:52		#7
sadeghsalehi New Member mohammad sadegh Join Date: Apr 2011 Posts: 5 Rep Power: 15	yes it must be activated in operating condition panel

October 10, 2012, 05:45		#8
nkme2007 Member Tamil Nadu Join Date: Oct 2012 Posts: 44 Rep Power: 13	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?