# set BC for fluidized bed

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 December 2, 2011, 22:05 set BC for fluidized bed #1 Member   Join Date: Oct 2011 Posts: 37 Rep Power: 7 hi. i tried to make fluidized bed simulation 2D.the geometry is simple:a cylinder 2D with inlet and outlet. BC are defined as flow: Inlet at the bed bottom is designated as Velocity Inlet boundary conditions for both the gas and solid phases. The boundary condition at the top of the bed is a pressure boundary ﬁxed at a reference value (atmospheric). Solids are free to leave if entrained and then return to the computational domain from the bottom inlet with a same mass ﬂux. how i can fix this in fluent??? i mean this condition ''Solids are free to leave if entrained and then return to the computational domain from the bottom inlet with a same mass ﬂux.'' thanks

 December 2, 2011, 23:52 Re #2 Senior Member   shoeb khan Join Date: Nov 2011 Posts: 179 Rep Power: 7 hi nice question but i have no idea. May be you can generate a udf for mass flow inlet in which the inlet mass flow can be computed from the mass flow from the outlet.Give the inlet mass flow of the solid same as the mas flowing out of the system. Try it i hope that works. SHK

 December 5, 2011, 04:33 #3 New Member   Sangram Roy Join Date: Jul 2010 Posts: 18 Rep Power: 8 are you trying to simulate a circulating fluidized bed? If so, in 2D you have a mention a certain solid velocity at the inlet assuming that they are always constant .

 December 6, 2011, 21:39 #4 Member   Join Date: Oct 2011 Posts: 37 Rep Power: 7 hi. shk, sangramory thanks for your reply. shk, i will try UDF and let u know. sangramory, yes I'm trying to simulate CFB. more exactly. the riser of CFB without the loop of return (i.e. cyclone, standpipe, feed device...) for this i need an adequate BC which can replace the loop of return.

 September 19, 2012, 05:23 #5 New Member   prishor p k Join Date: Jul 2012 Posts: 29 Rep Power: 6 Hi, I am doing my project in simulation of bubbling fluidized bed. i had made 2D geometry with meshes. Now the problem is that i have to include the bed material(sand) with initial bed height to the geometry before the simulation. Can anyone help me in this regard as I am new to FLUENT.

 September 19, 2012, 11:28 #6 New Member   Sangram Roy Join Date: Jul 2010 Posts: 18 Rep Power: 8 You have to 'patch' the regoin where you would like to have sand. The steps are as follows: 1) Adpat->Region-> Options-Inside-> Shapes-Hex-> Input coordinates( specify the coordinates to mark the region where solid is present)->Mark To check whether the region is correctly is marked, go to Manage-> select region -> Display. A new windows pops up showing the region marked. 2) Initialize the system. Then follow: Solve->Initialize->Patch-> Select solid phase-> select volume fraction under variable-> insert a value of volume fraction under 'value' -> select the region under 'Registers to patch'-> Patch. Its done. To check the correctness before starting the simulation, you can check the contour plots of solid volume fraction. Please remember, don't initialize again after patching. ramakant likes this.

 September 20, 2012, 00:55 #7 New Member   prishor p k Join Date: Jul 2012 Posts: 29 Rep Power: 6 Thank you Sangram..thank you very much...its a valuable information for me...once again thannxx.. regards, prishor

 September 20, 2012, 01:09 #8 New Member   prishor p k Join Date: Jul 2012 Posts: 29 Rep Power: 6 Dear Sangram, May I have your mail ID so that I can contact you for any clarifications. Thanks and regards, Prishor P K

 September 26, 2012, 09:39 #9 New Member   prishor p k Join Date: Jul 2012 Posts: 29 Rep Power: 6 Can anyone help to get some tutorial about analysis of Fluidized Bed Gasifier in FLUENT.. Please help me as I am new to this area

 September 28, 2012, 03:24 #10 New Member   rayolau Join Date: Aug 2012 Posts: 23 Rep Power: 6 Hi! I need do a patch for create a sand bed. It`s posible utilice patch and injections? Regards, Laura ramakant likes this.

March 8, 2016, 03:56
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Quote:
 Originally Posted by sangramroy You have to 'patch' the regoin where you would like to have sand. The steps are as follows: 1) Adpat->Region-> Options-Inside-> Shapes-Hex-> Input coordinates( specify the coordinates to mark the region where solid is present)->Mark To check whether the region is correctly is marked, go to Manage-> select region -> Display. A new windows pops up showing the region marked. 2) Initialize the system. Then follow: Solve->Initialize->Patch-> Select solid phase-> select volume fraction under variable-> insert a value of volume fraction under 'value' -> select the region under 'Registers to patch'-> Patch. Its done. To check the correctness before starting the simulation, you can check the contour plots of solid volume fraction. Please remember, don't initialize again after patching.
following this order, the region where is patched by sand will be marked, but how about the solids that are intended to fluidized? I mean how can I specify the region above the sands involving the solids at the initial state?
I have patched the region for the sands and I ended up with such result:
u (inlet air): 0.3 m/s
bulk density of solids: 100 kg/m3
run time: 1s

does it mean that the sands are also fluidizing?

 Tags boundary condition, fluent, fluidized beds

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