boundary conditions for cyclone separator

siddhukb · June 11, 2010, 03:27

i am doing a gas-solid simulation of cyclone separator. In the solution i get the mass is not balanced.
i have attached pics of the domain settings.
can someone help me in showing where i went wrong or what is the correct settings?

i have given a velocity inlet with both air and aluminium having 10m/s and air is 0.9 and aluminium is 0.1 volume fraction
both overflow and underflow i have given pressure outlet with pressure of 0atm
1.jpg

2.JPG

3.JPG

4.JPG

ghorrocks · June 14, 2010, 19:20

Please show your convergence results, and maybe post the CCL file.

siddhukb · June 15, 2010, 04:07

i have attached the ccl file

Thanks in advance
siddharth

-----------------------------
cyclone_multiphase_v5_1.zip

ghorrocks · June 15, 2010, 07:53

You are using a Reynolds Stress turbulence model. If you go to SST or some other more stable turbulence scheme it will be much more stable.

siddhukb · June 15, 2010, 08:11

but most of the journal i had studied suggested that Reynolds stress turbulence model is most suitable for cyclone separator

Thanks
siddharth

ghorrocks · June 15, 2010, 08:18

It is, but it will make convergence extremely difficult.

Get the basic model working with SST. Once everything is working with SST then switch back to RSM.

Also keep in mind that multiphase modelling introduces large simplifications. These simplifications can swamp the extra accuracy gained by RSM models. So if you have a have heavy multiphase interaction then I probably would not bother with RSM at all.

siddhukb · June 15, 2010, 08:53

will look into it.
I have one more doubt.
In the basic settings of the Domain -- Air is the continuous fluid. what should i define aluminium? cause i am confused in giving it as continuous fluid or dispersed solid or particle transport solid.

Thanks
siddharth

ghorrocks · June 15, 2010, 09:01

For a full answer to that question do a multiphase modelling course.

The quick answer is - light particle loadings - use particle tracking, heavy particle loadings use a Eularian approach.

June 11, 2010, 03:27	boundary conditions for cyclone separator	#1
siddhukb New Member siddharth Join Date: Jun 2010 Posts: 7 Rep Power: 16	i am doing a gas-solid simulation of cyclone separator. In the solution i get the mass is not balanced. i have attached pics of the domain settings. can someone help me in showing where i went wrong or what is the correct settings? i have given a velocity inlet with both air and aluminium having 10m/s and air is 0.9 and aluminium is 0.1 volume fraction both overflow and underflow i have given pressure outlet with pressure of 0atm 1.jpg 2.JPG 3.JPG 4.JPG

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June 14, 2010, 19:20		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	Please show your convergence results, and maybe post the CCL file.

June 15, 2010, 04:07		#3
siddhukb New Member siddharth Join Date: Jun 2010 Posts: 7 Rep Power: 16	i have attached the ccl file Thanks in advance siddharth ----------------------------- cyclone_multiphase_v5_1.zip

June 15, 2010, 07:53		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	You are using a Reynolds Stress turbulence model. If you go to SST or some other more stable turbulence scheme it will be much more stable.

June 15, 2010, 08:11		#5
siddhukb New Member siddharth Join Date: Jun 2010 Posts: 7 Rep Power: 16	but most of the journal i had studied suggested that Reynolds stress turbulence model is most suitable for cyclone separator Thanks siddharth

June 15, 2010, 08:18		#6
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	It is, but it will make convergence extremely difficult. Get the basic model working with SST. Once everything is working with SST then switch back to RSM. Also keep in mind that multiphase modelling introduces large simplifications. These simplifications can swamp the extra accuracy gained by RSM models. So if you have a have heavy multiphase interaction then I probably would not bother with RSM at all.

June 15, 2010, 08:53		#7
siddhukb New Member siddharth Join Date: Jun 2010 Posts: 7 Rep Power: 16	will look into it. I have one more doubt. In the basic settings of the Domain -- Air is the continuous fluid. what should i define aluminium? cause i am confused in giving it as continuous fluid or dispersed solid or particle transport solid. Thanks siddharth

June 15, 2010, 09:01		#8
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,854 Rep Power: 144	For a full answer to that question do a multiphase modelling course. The quick answer is - light particle loadings - use particle tracking, heavy particle loadings use a Eularian approach.